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This article presents the results of laboratory tests regarding the influence of high temperatures on changes in the strength and structural parameters of rocks that are present in the immediate vicinity of a gasification channel. Sandstone and claystone samples were heated at 300 °C, 600 °C, 900 °C and 1200 °C. Additionally, the heated samples were placed in water for 24 h. The results of the laboratory tests were used in the numerical simulation using RS2 software. The main goal of modeling was to determine the extent of the rock destruction zone around the gasification channel for dry and wet rock masses. In the numerical simulations, three widths of the gasification channel and three ranges of high-temperature impact were modeled. On the basis of the obtained results, it was found that the extent of rock destruction, both in the roof and in the floor, is greater by several percent for a wet rock mass. For the first time, this research presents the effect of water on heated rock samples in terms of the underground coal gasification process. The results of laboratory tests and numerical simulations clearly indicate a reduction in strength, deformation and structural parameters for the temperature of 1200 °C.

The article presents a novel yielding mechanism, especially designed for the rock bolt support. Mechanical rock bolts with an expansion head and equipped with one, two, four and six dome bearing plates were tested in the laboratory conditions. Furthermore, in the Phase2D numerical program, five room and pillar widths were modeled. The main aim of numerical modeling was to determine the maximal range of the rock damage area and the total displacements in the expanded room. The models were made for a room and pillar method with a roof sag for copper ore deposits in the Legnica-Głog&oacute, w Copper District in Poland. Additionally, in the article a load model of the rock bolt support as a result of a geomechanical seismic event is presented. Based on the results of laboratory tests (load &ndash, displacement characteristics), the strain energy of the bolt support equipped with the yielding device in the form of dome bearing plates was determined and compared with the impact energy caused by predicted falling rock layers. Based on the laboratory tests, numerical modeling and mathematical dynamic model of rock bolt support, the dependence of the drop height and the corresponding impact energy for the expanded room was determined.

The TAM receptor tyrosine kinases (RTK) Mer and Axl have been implicated in liver disease, yet our understanding of their roles in liver homeostasis and injury is limited. We therefore examined the performance of Mer and Axl mutant mice during aging, and in four models of liver injury. We find that Mer and Axl are most prominently expressed in Kupffer and hepatic endothelial cells, and that asAxl-/-Mertk-/-mice normally age, they develop profound liver disease. We further find that Mer signaling is critical to the phagocytosis of apoptotic hepatocytes that are generated during acute hepatic injury, and that Mer and Axl act in concert to inhibit injury-triggered cytokine production. TAM expression in Kupffer cells is crucial for these effects. In contrast, we show that Axl is uniquely important in mitigating liver damage during acute acetaminophen intoxication. Finally, we demonstrate that Axl exacerbates the fibrosis that develops in a model of chronic hepatic injury. These divergent effects have important implications for the design and implementation of TAM-directed therapeutics that target these RTKs in the liver.

Genome-wide association studies have implicated the TAM receptor tyrosine kinase (RTK) Mer in liver disease, yet our understanding of the role that Mer and its related RTKs Tyro3 and Axl play in liver homeostasis and the response to acute injury is limited. We find that Mer and Axl are most prominently expressed in hepatic Kupffer and endothelial cells and that as mice lacking these RTKs age, they develop profound liver disease characterized by apoptotic cell accumulation and immune activation. We further find that Mer is critical to the phagocytosis of apoptotic hepatocytes generated in settings of acute hepatic injury, and that Mer and Axl act in concert to inhibit cytokine production in these settings. In contrast, we find that Axl is uniquely important in mitigating liver damage during acetaminophen intoxication. Although Mer and Axl are protective in acute injury models, we find that Axl exacerbates fibrosis in a model of chronic injury. These divergent effects have important implications for the design and implementation of TAM-directed therapeutics that might target these RTKs in the liver., This work was supported by grants from the NIH (R01 NS085296, R01 AI101400, and P30CA014195), the Leona M and Harry B Helmsley Charitable Trust (#2012-PG-MED002), the Nomis, HN and Frances C Berger, Fritz B Burns, and HKT Foundations (to G Lemke) and by postdoctoral fellowships from the Marie Curie International Outgoing Fellowship Program (to PG Través), the Nomis Foundation (to A Zagórska), and the Fundación Alfonso Martín Escudero (to L Jiménez-García).

The Seve Nappe Complex exposed in the Kitt&auml, lfjall area of the northern Scandinavian Caledonides comprises a volcano-sedimentary succession representing the Baltica passive margin, which was metamorphosed during the Iapetus Ocean closure. Garnet amphibolites, together with their host migmatitic paragneisses, record a potential (U)HP event followed by decompression-driven migmatization. The garnet amphibolites were originally thought to represent retrogressively altered granulites. The petrological and geochemical features of a studied garnet amphibolite allow for speculation about a peridotitic origin. Zirconium (Zr) content in rutile inclusions hosted in garnet in paragneisses points to near-peak temperatures between 738 &deg, C and 780 &deg, C, which is in agreement with the c. 774 &deg, C obtained from the matrix rutile in the garnet amphibolite. The matrix rutile in multiple paragneiss samples records temperatures below 655 &deg, C and 726 &deg, C. Whereas the LA-ICP-MS U-Pb dating of zircon cores revealed the age spectrum from Paleoproterozoic to early Paleozoic, suggesting a detrital origin of zircon cores in paragneisses, the metamorphic zircon rims show an Early Ordovician cluster c. 475&ndash, 469 Ma. Additionally, zircon cores and rims from the garnet amphibolite yielded an age of c. 473 Ma. The REE patterns of the Caledonian zircon rims from the paragneisses show overall low LREE concentrations, different from declining to rising trends in HREE (LuN/GdN = 0.49&ndash, 38.76). Despite the textural differences, the cores and rims in zircon from the garnet amphibolite show similar REE patterns of low LREE and flat to rising HREE (LuN/GdN = 3.96&ndash, 65.13). All zircon rims in both lithologies display a negative Eu anomaly. Hence, we interpret the reported ages as the growth of metamorphic zircon during migmatization, under granulite facies conditions related to exhumation from (U)HP conditions.

Apatites from Martian nakhlites NWA 10153 and NWA 10645 were used to obtain insight into their crystallization environment and the subsequent postcrystallization evolution path. The research results acquired using multi-tool analyses show distinctive transformation processes that were not fully completed. The crystallization history of three apatite generations (OH-bearing, Cl-rich fluorapatite as well as OH-poor, F-rich chlorapatite and fluorapatite) were reconstructed using transmission electron microscopy and geochemical analyses. Magmatic OH-bearing, Cl-rich fluorapatite changed its primary composition and evolved toward OH-poor, F-rich chlorapatite because of its interaction with fluids. Degassing of restitic magma causes fluorapatite crystallization, which shows a strong structural affinity for the last episode of system evolution. In addition to the three apatite generations, a fourth amorphous phase of calcium phosphate has been identified with Raman spectroscopy. This amorphous phase may be considered a transition phase between magmatic and hydrothermal phases. It may give insight into the dissolution process of magmatic phosphates, help in processing reconstruction, and allow to decipher mineral interactions with hydrothermal fluids.

This paper presents the results of laboratory tensile testing of segmentally-installed glue-in roof bolting. We studied roof bolting of the type Olkusz-16A (Boltech Sp. z o.o., ZGH Bolesław S.A., Bukowno, Poland), additionally equipped with a steel rod coil, which was mounted in steel cylinders filled with a concrete mixture using multi-part resin cartridges with a diameter of 0.024 m and length of 0.045 m. The mounting depths were 0.1 m and 0.2 m, respectively. Our main purpose was to determine the effect of the bolt hole diameter, which assumed the values 0.028 m, 0.032 m, 0.035 m, and 0.037 m, respectively, on the load-bearing capacity of the roof bolting in relation to the mounting depth. We found that the mounting depth of 0.2 m was sufficient for the roof bolting to exhibit its full load and displacement properties for all four diameters of the bolt hole. To determine whether the roof bolting was capable of transferring the load in situ, we presented the results of the predicted load on the roof bolting applied in a room and pillar mining method in an underground mine of zinc and lead ore deposits. Our objective was to determine the influence of the room and pillar mining method geometry on the range of the fault zone of rocks around pits. We designed the deposit excavation model using the Examine3D numerical modeling software, which is based on the boundary element method. We created three-dimensional models for three variants of working space opening widths: featuring two, three, and four rows of rooms. The geometry of rooms and pillars corresponded to the mine conditions, the width, height, and length parameters were all 5 m. We determined the strength, strain, and structural parameters of the rock mass on the basis of laboratory studies of the drill core and rock forms collected from the room longwall. We used the strength factor to specify the maximum range of the fault zone of rocks around pits. In the last stage of research, we compared the load value obtained based on numerical testing with the maximum load obtained in the tensile strength tests of the roof bolting and determined the safety factor of the segmentally-installed roof bolting.

Microglia are damage sensors for the central nervous system (CNS), and the phagocytes responsible for routine non-inflammatory clearance of dead brain cells. Here we show that the TAM receptor tyrosine kinases Mer and Axl regulate these microglial functions. We find that adult mice deficient in microglial Mer and Axl exhibit a marked accumulation of apoptotic cells specifically in neurogenic regions of the CNS, and that microglial phagocytosis of the apoptotic cells generated during adult neurogenesis is normally driven by both TAM receptor ligands Gas6 and protein S. Using live two-photon imaging, we demonstrate that the microglial response to brain damage is also TAM-regulated, as TAM-deficient microglia display reduced process motility and delayed convergence to sites of injury. Finally, we show that microglial expression of Axl is prominently upregulated in the inflammatory environment that develops in a mouse model of Parkinson's disease. Together, these results establish TAM receptors as both controllers of microglial physiology and potential targets for therapeutic intervention in CNS disease.

Southeastern Bulgaria is composed of a variety of rocks from pre-Variscan (ca. 0.3 Ga) to pre-Alpine sensu lato (ca. 0.15 Ga) time. The Sakar Unit in this region comprises a series of granitoids and gneisses formed or metamorphosed during these events. It is cut by a series of post-Variscan hydrothermal veins, yet lacks pervasive Alpine deformation. It thus represents a key unit for detecting potential tectonism associated with the enigmatic Cimmerian Orogenic episode, but limited geochronology has been undertaken on this unit. Here we report age constraints on hydrothermal activity in the Sakar Pluton. The investigated veins contain mainly albite&ndash, actinolite&ndash, chlorite&ndash, apatite&ndash, titanite&ndash, quartz&ndash, tourmaline&ndash, epidote and accessory minerals. The most common accessory minerals are rutile and molybdenite. Apatite and titanite from the same vein were dated by U&ndash, Pb LA&ndash, ICP-MS geochronology. These dates are interpreted as crystallization ages and are 149 &plusmn, 7 Ma on apatite and 114 &plusmn, 1 Ma on titanite, respectively. These crystallization ages are the first to document two stages of hydrothermal activity during the late Jurassic to early Cretaceous, using U&ndash, Pb geochronology, and its association with the Cimmerian orogenesis. The Cimmerian tectono-thermal episode is well-documented further to the east in the Eastern Strandja Massif granitoids. However, these are the first documented ages from the western parts of the Strandja Massif, in the Sakar Unit. These ages also temporally overlap with previously published Ar&ndash, Ar and K&ndash, Ar cooling ages, and firmly establish that the Cimmerian orogeny in the studied area included both tectonic and hydrothermal activity. Such hydrothermal activity likely accounted for the intense albitization found in the Sakar Unit.

SummaryHistidine phosphorylation (pHis) is well studied in bacteria; however, its role in mammalian signaling remains largely unexplored due to the lack of pHis-specific antibodies and the lability of the phosphoramidate (P-N) bond. Both imidazole nitrogens can be phosphorylated, forming 1-phosphohistidine (1-pHis) or 3-phosphohistidine (3-pHis). We have developed monoclonal antibodies (mAbs) that specifically recognize 1-pHis or 3-pHis; they do not cross-react with phosphotyrosine or the other pHis isomer. Assays based on the isomer-specific autophosphorylation of NME1 and phosphoglycerate mutase were used with immunoblotting and sequencing IgG variable domains to screen, select, and characterize anti-1-pHis and anti-3-pHis mAbs. Their sequence independence was determined by blotting synthetic peptide arrays, and they have been tested for immunofluorescence staining and immunoaffinity purification, leading to putative identification of pHis-containing proteins. These reagents should be broadly useful for identification of pHis substrates and functional study of pHis using a variety of immunological, proteomic, and biological assays.

Presented studies investigated the specificity of visual and auditory modalities in attentional processing of emotion, and its association with temperamental dimensions and trait-like attentional control (AC). During preliminary study 30 participants were presented with the paper-pencil visual search task (Emotional Faces Attentional Test) and emotional prosody detection tasks (Emotional Prosody Test). Results revealed visual happiness superiority and auditory sadness superiority. During the main study, in addition to attentional performance, 51 subjects were administrated two questionnaires: EPQ-R and Attentional Control Scale. Introducing individual differences into analysis limited the general pattern of modality distinctiveness in attentional processing of emotional stimuli obtained in the preliminary study. Findings for all personality traits studied separately showed that Extraversion and low Neuroticism were associated with the visual sadness superiority. Whereas interactional analysis indicated effective visual threat processing in extraverts with good AC and effective friendly prosody detection when Neuroticism and AC remain in inverse relationship. Hence, we have found that processing emotional targets in both modalities is associated with temperament dimensions and their interactions with attentional control. Additionally, findings from both studies suggest that general psychological laws might be challenged by individual differences.

Apoptotic cell clearance is critical for both tissue homeostasis and the resolution of inflammation. We found that the TAM receptor tyrosine kinases Axl and Mer played distinct roles as phagocytic receptors in these two settings, where they exhibited divergent expression, regulation, and activity. Mer acted as a tolerogenic receptor in resting macrophages and in settings of immune suppression. Conversely, Axl was an inflammatory response receptor whose expression was induced by pro-inflammatory stimuli. Axl and Mer displayed distinct ligand specificities, ligand-receptor complex formation in tissues, and receptor shedding upon activation. These differences notwithstanding, phagocytosis by either protein was strictly dependent on receptor activation that was triggered by bridging TAM receptor–ligand complexes to the ‘eat-me’ signal phosphatidylserine on apoptotic cell surfaces.

NUAK1 (NUAK family SnF1-like kinase-1) and NUAK2 protein kinases are activated by the LKB1 tumour suppressor and have been implicated in regulating multiple processes such as cell survival, senescence, adhesion and polarity. In the present paper we present evidence that expression of NUAK1 is controlled by CDK (cyclin-dependent kinase), PLK (Polo kinase) and the SCFβTrCP (Skp, Cullin and F-boxβTrCP) E3 ubiquitin ligase complex. Our data indicate that CDK phosphorylates NUAK1 at Ser445, triggering binding to PLK, which subsequently phosphorylates NUAK1 at two conserved non-catalytic serine residues (Ser476 and Ser480). This induces binding of NUAK1 to βTrCP, the substrate-recognition subunit of the SCFβTrCP E3 ligase, resulting in NUAK1 becoming ubiquitylated and degraded. We also show that NUAK1 and PLK1 are reciprocally controlled in the cell cycle. In G2–M-phase, when PLK1 is most active, NUAK1 levels are low and vice versa in S-phase, when PLK1 expression is low, NUAK1 is more highly expressed. Moreover, NUAK1 inhibitors (WZ4003 or HTH-01-015) suppress proliferation by reducing the population of cells in S-phase and mitosis, an effect that can be rescued by overexpression of a NUAK1 mutant in which Ser476 and Ser480 are mutated to alanine. Finally, previous work has suggested that NUAK1 phosphorylates and inhibits PP1βMYPT1 (where PP1 is protein phosphatase 1) and that a major role for the PP1βMYPT1 complex is to inhibit PLK1 by dephosphorylating its T-loop (Thr210). We demonstrate that activation of NUAK1 leads to a striking increase in phosphorylation of PLK1 at Thr210, an effect that is suppressed by NUAK1 inhibitors. Our data link NUAK1 to important cell-cycle signalling components (CDK, PLK and SCFβTrCP) and suggest that NUAK1 plays a role in stimulating S-phase, as well as PLK1 activity via its ability to regulate the PP1βMYPT1 phosphatase., The present study provides insights into the biological regulation of the NUAK isoforms and highlights the remarkable interplay that exists between Polo kinase, NUAK1, PP1βMYPT1 and SCFβTrCP signalling components. It demonstrates NUAK1 inhibitors suppress cell proliferation and PLK1.

SummaryUpon activation by the ligands Gas6 and Protein S, Tyro3/Axl/Mer (TAM) receptor tyrosine kinases promote phagocytic clearance of apoptotic cells and downregulate immune responses initiated by Toll-like receptors and type I interferons (IFNs). Many enveloped viruses display the phospholipid phosphatidylserine on their membranes, through which they bind Gas6 and Protein S and engage TAM receptors. We find that ligand-coated viruses activate TAM receptors on dendritic cells (DCs), dampen type I IFN signaling, and thereby evade host immunity and promote infection. Upon virus challenge, TAM-deficient DCs display type I IFN responses that are elevated in comparison to wild-type cells. As a consequence, TAM-deficient DCs are relatively resistant to infection by flaviviruses and pseudotyped retroviruses, but infection can be restored with neutralizing type I IFN antibodies. Correspondingly, a TAM kinase inhibitor antagonizes the infection of wild-type DCs. Thus, TAM receptors are engaged by viruses in order to attenuate type I IFN signaling and represent potential therapeutic targets.

Axl expression is induced by TGF-β1 during Langerhans cell differentiation and enhances apoptotic cell uptake and blocks proinflammatory cytokine production., Transforming growth factor-β1 (TGF-β1) is a fundamental regulator of immune cell development and function. In this study, we investigated the effects of TGF-β1 on the differentiation of human Langerhans cells (LCs) and identified Axl as a key TGF-β1 effector. Axl belongs to the TAM (Tyro3, Axl, and Mer) receptor tyrosine kinase family, whose members function as inhibitors of innate inflammatory responses in dendritic cells and are essential to the prevention of lupus-like autoimmunity. We found that Axl expression is induced by TGF-β1 during LC differentiation and that LC precursors acquire Axl early during differentiation. We also describe prominent steady-state expression as well as inflammation-induced activation of Axl in human epidermal keratinocytes and LCs. TGF-β1–induced Axl enhances apoptotic cell (AC) uptake and blocks proinflammatory cytokine production. The antiinflammatory role of Axl in the skin is reflected in a marked impairment of the LC network preceding spontaneous skin inflammation in mutant mice that lack all three TAM receptors. Our findings highlight the importance of constitutive Axl expression to tolerogenic barrier immunity in the epidermis and define a mechanism by which TGF-β1 enables silent homeostatic clearing of ACs to maintain long-term self-tolerance.

Eysenck’s PEN and Strelau’s RTT theories are considered interrelated on the level of traits and translatable on the level of four ancient temperament types. However, they refer to different ways of regulation stimulation, by content (emotional and social) and by the formal (energetic and temporal) characteristics of activity, respectively. Thus, by indexing behavioral and cortical patterns of response, it was predicted that PEN- and RTT-relevant pairs of temperaments would be associated with specific attentional mechanisms. One week after administration of the FCB-TI and EPQ-R, subjects (260) performed the Emotional Go/No Go task while a 32-channel EEG was being recorded. They were instructed to respond to threatening, sad, or friendly faces, respectively, but not to any other facial expression. A range of ERP components responsive to facial stimuli were investigated. According to behavioral and cortical patterns of response, it was shown that PEN- and RTT-related pairs of temperament types were connected with effective functioning of the anterior and posterior attentional system, respectively. On the behavioral level, significant differences in attentional processing of facial affect were registered in PEN sanguines versus RTT sanguines and PEN melancholics versus RTT melancholics, while on the cortical level significant differences were registered in PEN melancholics versus RTT melancholics and PEN phlegmatics versus RTT phlegmatics. Given these results, the theoretical relations between the PEN and RTT – with particular respect to cognitive and cortical mechanisms underlying temperament types – are discussed.

A range of ERP components responsive to facial stimuli and indexing the rapid attentional engagement (P1, N170), the increased (N400) and sustained (LPC) attention allocation and attentional control (N2) was investigated among low-anxious (LAs), high-anxious (HAs), repressors (REPs), and defensive high-anxious (DHAs) individuals. One week after questionnaire administration, EEG signals were recorded while Ss (N = 102) were administrated the Emotional Go/NoGo task. They were instructed to respond to threatening, sad or friendly faces, respectively but not respond to any other facial expression. REPs presented enhanced responsivity to threatening and happy faces in several prefrontal areas, thus complementing the behavioral response data. Based on the behavioral and cortical indices the expected later attentional avoidance bias for threat in REPs and a difficulty in attention disengagement from threat in HAs were not confirmed. Moreover, REPs and HAs exhibited more bottom-up cortical regulation and more right-lateralized activation than DHAs in the processing of facial threat. In addition, there were non-significant results for DHAs on behavioral measures. However, they were cortically reactive to all facial expressions and not specifically to threat. Present results suggest that behavioral and brain levels of explanation should be carefully taken into account in further studies on anxiety.

AMPK (AMP-activated protein kinase)-related kinases regulate cell polarity as well as proliferation and are activated by the LKB1-tumour suppressor kinase. In the present study we demonstrate that the AMPK-related kinases, NUAK1 (AMPK-related kinase 5) and MARK4 (microtubule-affinity-regulating kinase 4), are polyubiquitinated in vivo and interact with the deubiquitinating enzyme USP9X (ubiquitin specific protease-9). Knockdown of USP9X increased polyubiquitination of NUAK1 and MARK4, whereas overexpression of USP9X inhibited ubiquitination. USP9X, catalysed the removal of polyubiquitin chains from wild-type NUAK1, but not from a non-USP9X-binding mutant. Topological analysis revealed that ubiquitin monomers attached to NUAK1 and MARK4 are linked by Lys29 and/or Lys33 rather than the more common Lys48/Lys63. We find that AMPK and other AMPK-related kinases are also polyubiquitinated in cells. We identified non-USP9X-binding mutants of NUAK1 and MARK4 and find that these are hyper-ubiquitinated and not phosphorylated at their T-loop residue targeted by LKB1 when expressed in cells, suggesting that polyubiquitination may inhibit these enzymes. The results of the present study demonstrate that NUAK1 and MARK4 are substrates of USP9X and provide the first evidence that AMPK family kinases are regulated by unusual Lys29/Lys33-linked polyubiquitin chains.

Mutations within the WNK1 (with-no-K[Lys] kinase-1) gene cause Gordon's hypertension syndrome. Little is known about how WNK1 is regulated. We demonstrate that WNK1 is rapidly activated and phosphorylated at multiple residues after exposure of cells to hyperosmotic conditions and that activation is mediated by the phosphorylation of its T-loop Ser382 residue, possibly triggered by a transautophosphorylation reaction. Activation of WNK1 coincides with the phosphorylation and activation of two WNK1 substrates, namely, the protein kinases STE20/SPS1-related proline alanine–rich kinase (SPAK) and oxidative stress response kinase-1 (OSR1). Small interfering RNA depletion of WNK1 impairs SPAK/OSR1 activity and phosphorylation of residues targeted by WNK1. Hyperosmotic stress induces rapid redistribution of WNK1 from the cytosol to vesicular structures that may comprise trans-Golgi network (TGN)/recycling endosomes, as they display rapid movement, colocalize with clathrin, adaptor protein complex 1 (AP-1), and TGN46, but not the AP-2 plasma membrane–coated pit marker nor the endosomal markers EEA1, Hrs, and LAMP1. Mutational analysis suggests that the WNK1 C-terminal noncatalytic domain mediates vesicle localization. Our observations shed light on the mechanism by which WNK1 is regulated by hyperosmotic stress.

The TAM receptor tyrosine kinases Tyro3, Axl, and Mer regulate key features of cellular physiology, yet the differential activities of the TAM ligands Gas6 and Protein S are poorly understood. We have used biochemical and genetic analyses to delineate the rules for TAM receptor–ligand engagement and find that the TAMs segregate into two groups based on ligand specificity, regulation by phosphatidylserine, and function. Tyro3 and Mer are activated by both ligands but only Gas6 activates Axl. Optimal TAM signaling requires coincident TAM ligand engagement of both its receptor and the phospholipid phosphatidylserine (PtdSer): Gas6 lacking its PtdSer-binding ‘Gla domain’ is significantly weakened as a Tyro3/Mer agonist and is inert as an Axl agonist, even though it binds to Axl with wild-type affinity. In two settings of TAM-dependent homeostatic phagocytosis, Mer plays a predominant role while Axl is dispensable, and activation of Mer by Protein S is sufficient to drive phagocytosis. DOI: http://dx.doi.org/10.7554/eLife.03385.001, eLife digest Cells send out and receive signals to communicate with other cells. Detecting these signals is largely carried out by proteins called receptors that span the cell surface membrane. These proteins typically have extracellular domains outside of the cell that can bind to specific signaling molecules and an intracellular domain inside the cell that relays the information inwards to trigger a response. Three such receptor proteins are collectively known as the TAM receptors. Each day, many billions of cells in the human body die and are engulfed by other cells and broken down so that their building blocks can be reused. TAM receptors are required for this process; and the TAM receptors also help prevent the immune system from going out of control, which would damage the body's own tissues. Two different signaling proteins, called Gas6 and Protein S, can bind to and activate TAM receptors. Both of the signaling proteins can also bind to a phospholipid molecule that is found on the surface membrane of dead cells. However, it is not known if all three TAM receptors bind to both signaling proteins equally, and the importance of the phospholipid-binding domain in the signaling proteins remains unclear. To shed light on the workings of these receptors, Lew et al. created mouse cells that each only express one out of the three TAM receptors. These cells were then exposed to intact Gas6 and Protein S, or shortened versions that lacked the phospholipid-binding domain. Lew et al. found that Gas6 could trigger a response through all three TAM receptors but that Protein S was specific for only two out of the three receptors. Signaling proteins with or without their phospholipid-binding domains bound equally well to the receptors, but the maximum level of response was only triggered when both signaling proteins were intact and the phospholipid molecule was present. This is important since the phospholipid can be thought of as an ‘eat-me’ signal by which the dead cells are recognized by the TAM receptor-expressing cells that will engulf them. Using mice that only produce a TAM receptor called Mer, Lew et al. show that Protein S alone can trigger the process that engulfs and breaks down cells in a living organism. These data and previous work suggest that two TAM receptors—including Mer—are involved in the daily engulfment of dying cells, whereas the third mediates this process during infection and tissue damage. Molecules that inhibit or activate the function of TAM receptors are currently being developed to treat cancer and other diseases. By revealing which receptors respond to which signaling molecules, the findings of Lew et al. will serve to guide these efforts. DOI: http://dx.doi.org/10.7554/eLife.03385.002

Introduction Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by an unrestrained inflammatory response in synovial joints. One family of tyrosine kinase receptors involved in anti-inflammatory feedback mechanism are Tyro3, Axl and Mer (TAM). The plasma level of the TAM receptor ligand Gas6 is significantly reduced in RA patients suggesting this feedback mechanism is impaired in RA. We investigated the individual role of each TAM receptor in experimental arthritis. Methods The KRN serum transfer model of arthritis was induced by two intraperitoneal injections of arthritic K/BxN serum in TAM receptor single gene knock-out mice (Tyro3−/−, Axl−/−, Mer−/−) and wild-type (WT) mice. Ankle joints were macroscopically scored for 7 days and knee and ankle joints were taken at the end of the experiment for histology and immunohistochemistry. Results Mer−/− mice had an increased macroscopic ankle score until day 4 whereas Axl−/− mice had an enhanced macroscopic score from day 4 until the end of the experiment. Histology of the ankle joints showed significantly increased arthritis pathology in Axl−/− mice compared to WT. In contrast, enhanced macroscopic score and arthritis pathology in the knee joints of Mer−/− mice was observed. Both in ankle and knee joints, no protective or aggravating role of Tyro3 was seen. To explain the discrepancy of Axl involvement between ankle and knee, we looked for Axl expression in synovium of naïve mice. The lining layer of ankle synovium was completely Axl-positive whereas only mild expression in the knee joints was observed. Conclusion These findings identify the TAM receptors Axl and Mer as important protective players in arthritis in addition to being expressed in a joint-specific manner.

The AMPK-related kinases NUAK1 and NUAK2 are activated by the tumor suppressor LKB1. We found that NUAK1 interacts with several myosin phosphatases, including the myosin phosphatase targeting-1 (MYPT1)-protein phosphatase-1beta (PP1beta) complex, through conserved Gly-Ile-Leu-Lys motifs that are direct binding sites for PP1beta. Phosphorylation of Ser(445), Ser(472), and Ser(910) of MYPT1 by NUAK1 promoted the interaction of MYPT1 with 14-3-3 adaptor proteins, thereby suppressing phosphatase activity. Cell detachment induced phosphorylation of endogenous MYPT1 by NUAK1, resulting in 14-3-3 binding to MYPT1 and enhanced phosphorylation of myosin light chain-2. Inhibition of the LKB1-NUAK1 pathway impaired cell detachment. Our data indicate that NUAK1 controls cell adhesion and functions as a regulator of myosin phosphatase complexes. Thus, LKB1 can influence the phosphorylation of targets not only through the AMPK family of kinases but also by controlling phosphatase complexes.

Somites are embryonic precursors of the ribs, vertebrae and certain dermis tissue. Somite formation is a periodic process regulated by a molecular clock which drives cyclic expression of a number of clock genes in the presomitic mesoderm. To date the mechanism regulating the period of clock gene oscillations is unknown. Here we show that chick homologues of the Wnt pathway genes that oscillate in mouse do not cycle across the chick presomitic mesoderm. Strikingly we find that modifying Wnt signalling changes the period of Notch driven oscillations in both mouse and chick but these oscillations continue. We propose that the Wnt pathway is a conserved mechanism that is involved in regulating the period of cyclic gene oscillations in the presomitic mesoderm.

Irreversible HER/erbB inhibitors selectively inhibit HER-family kinases by targeting a unique cysteine residue located within the ATP-binding pocket. Sequence alignment reveals that this rare cysteine is also present in ten other protein kinases including all five Tec-family members. We demonstrate that the Tec-family kinase Bmx is potently inhibited by irreversible modification at Cys496 by clinical stage EGFR inhibitors such as CI-1033. This cross-reactivity may have significant clinical implications.

Small ubiquitin-like modifier (SUMO)-specific protease SENP1 processes SUMO-1, SUMO-2 and SUMO-3 to mature forms and deconjugates them from modified proteins. To establish the proteolytic mechanism, we determined structures of catalytically inactive SENP1 bound to SUMO-1-modified RanGAP1 and to unprocessed SUMO-1. In each case, the scissile peptide bond is kinked at a right angle to the C-terminal tail of SUMO-1 and has the cis configuration of the amide nitrogens. SENP1 preferentially processes SUMO-1 over SUMO-2, but binding thermodynamics of full-length SUMO-1 and SUMO-2 to SENP1 and K(m) values for processing are very similar. However, k(cat) values differ by 50-fold. Thus, discrimination between unprocessed SUMO-1 and SUMO-2 by SENP1 is based on a catalytic step rather than substrate binding and is likely to reflect differences in the ability of SENP1 to correctly orientate the scissile bonds in SUMO-1 and SUMO-2.