Search

Acute myeloid leukemia (AML) is a hematologic malignant disease largely affecting older adults with poor outcomes. Lack of effective targeted treatment is a major challenge in managing the disease in the clinic. Scaffolding adaptor Gab2 is amplified in a subset of AML. However, the causative role of Gab2 in AML remains to be explored. In this study, it was found that Gab2 was expressed at high levels in AML patient samples and AML cell lines. Experiments by knocking down Gab2 expression using shRNA showed that Gab2 promoted AML cell growth and migration in vitro and in vivo. Further studies using Gab2 mutants and pharmacological inhibitors revealed that Gab2 increased CREB phosphorylation via the SHP‐2/Erk signaling pathway. CREB phosphorylation contributed to Gab2‐induced cell migration by increasing MMP2 and MMP9 expression. This research indicates that high Gab2 expression promotes AML progression through the SHP2‐Erk‐CREB signaling pathway. CREB suppression may help treat AML with high Gab2 expression. Data to support model that Gab2 promotes AML progression through the SHP2‐Erk‐CREB pathway.

Metastasis is responsible for the death of most breast cancer patients. Robo1 has been implicated as a tumor suppressor for various cancers including breast cancer. However, it is not well understood how Robo1 expression is regulated during tumorigenesis. In this study, we uncovered that the transmembrane proline rich ?-carboxyglutamic acid protein 4 (PRRG4) promotes breast cancer metastasis by downregulating Robo1. Analysis of mRNA expression data in The Cancer Genome Atlas and immunohistochemistry assay on breast tumor samples showed that PRRG4 expression was higher in breast tumors than in normal breast tissues. Experiments with PRRG4 knockdown and overexpression revealed that PRRG4 promoted migration and invasion of breast cancer cells, and enhanced metastasis in an experimental metastasis model. Mechanistically, we found that PRRG4 via its LPSY and PPPY motifs recruited the E3 ubiquitin ligase NEDD4, which induced ubiquitination and degradation of Robo1, thus contributing to migration and invasion of breast cancer cells. In addition, PRRG4 interacted with and enhanced protein tyrosine kinase Src and FAK activation. Overall, our data support a model that PRRG4 via NEDD4 downregulates the Robo1, resulting in the activation of Src and FAK and promoting breast cancer metastasis. PRRG4 may be a novel target for treating metastatic breast cancer.

Public key cryptographic (PKC) algorithms, such as the RSA, elliptic curve digital signature algorithm (ECDSA) etc., are widely used in the secure communication systems, such as OpenSSL, and a variety of information security systems. If designer do not securely implement them, the secret key will be easily extracted by side-channel attacks (SCAs) or combinational SCA thus mitigating the security of the entire communication system. Previous countermeasures of PKC implementations focused on the core part of the algorithms and ignored the modular inversion which is widely used in various PKC schemes. Many researchers believe that instead of straightforward implementation, constant time modular inversion (CTMI) is enough to resist the attack of simple power analysis combined with lattice analysis. However, we find that the CTMI security can be reduced to a hidden t-bit multiplier problem. Based on this feature, we firstly obtain Hamming weight of intermediate data through side-channel leakage. Then, we propose a heuristic algorithm to solve the problem by revealing the secret (partial and full) base of CTMI. Comparing previous necessary input message for masking filtering, our procedure need not any information about the secret base of the inversion. To our knowledge, this is the first time for evaluating the practical security of CTMI and experimental results show the fact that CTMI is not enough for high-level secure communication systems.

A template attack, the most powerful side-channel attack methods, usually first builds the leakage profiles from a controlled profiling device, and then uses these profiles to recover the secret of the target device. It is based on the fact that the profiling device shares similar leakage characteristics with the target device. In this study, we focus on the similar operations in a single device and propose a new variant of the template attack, called the similar operation template attack (SOTA). SOTA builds the models on public variables (e.g., input/output) and recovers the values of the secret variables that leak similar to the public variables. SOTA’s advantage is that it can avoid the requirement of an additional profiling device. In this study, the proposed SOTA method is applied to a straightforward RSA-CRT implementation. Because the leakage is (almost) the same in similar operations, we reduce the security of RSA-CRT to a hidden multiplier problem (HMP) over GF(q), which can be solved byte-wise using our proposed heuristic algorithm. The effectiveness of our proposed method is verified as an entire prime recovery procedure in a practical leakage scenario.

Power analysis is a non-invasive attack against cryptographic hardware, which effectively exploits runtime power consumption characteristics of circuits. This paper proposes a new power model which combines Hamming Distance model and the model based on the template value of power consumption in combinational logic circuit. The new model can describe the power consumption characteristics of sequential logic circuits and those of combinational logic as well. The new model can be used to improve the existing power analysis methods and detect the information leakage of power consumption. Experimental results show that, compared to CPA(Correlation Power Analysis) method, our proposed attack which adopt the combinational model is more efficient in terms of the number of required power traces.

In this paper, we propose a hybrid power model that includes the power consumption of not only the registers but also part of the combinational logic. By doing knownkey analysis with this hybrid model, power side-channel leakage caused by correct keys can be detected. In experiment, PRINTcipher and DES algorithms were chosen as analysis targets and combinational logic s-box unit was selected to build power template. The analysis results showed the signal-to-noise ratio (SNR) power consumption increase of more than 20% after considering s-box’s power consumption so that the information of keys can be obtained with just half number of power traces. In addition, the side channel-leakage detection capability of our method also shows better effectiveness that can identify the correct keys.

With the acceleration of globalization and regionalization of the world economy, port is playing an increasingly important role for that it is an international transportation hub port interface and the support of the international trade platform. How to effectively reduce labor costs, improve the working environment, stable productivity, reduce the production cuts caused by human intervention and improve the management of real-time monitoring of all the major ports has become a common issue faced. In order to achieve the automatically stacking and reclaiming process of Stacker-Reclaimer in the bulk material yard, the source of its control is expected to identify the stockpile in the bulk yard, including length, width, height, the starting address, destination address, as well as Three-dimensional shape of the stockpile, since in the operation process, stockpile changes the shape dynamically. As a result, the real-time three-dimensional shape and coordinate of piles should be achieved. Based on the existing Stacker-Reclaimer in Qinhuangdao Port coal, we study the large field of view real-time three-dimensional laser scanning imaging theory and technology. The overall system design to achieving the three-dimensional laser scanning image is presented. The working principle of the three-dimensional laser scanning imaging system is analysised. Moreover, the parameter designation, the technical parameters and the composition of the whole system are all given. The research of the thesis is also used for other large-scale three-dimensional modeling of piles and the volume computing. In a world, the method has wide application prospect.

Mediastinal unicentric Castleman disease (UCD) frequently manifests as a hyper-enhancing lymph node mass and is often surgically curable. However, because of excessive vascularisation and adhesion to important surrounding structures, surgery is often associated with severe haemorrhage that is often difficult to control thoracoscopically. Therefore, thoracotomy is often preferred, which increases the trauma to the patient and affects postoperative recovery. Here, we describe the case of a 30-year-old male patient with a large upper mediastinal lymph node (7 × 5 × 4 cm) that was compressing his superior vena cava. The distribution of nutritive arteries of the mass was analysed in detail, and the main branches were embolised prior to surgery. With the assistance of preoperative isovolumetric haemodilution, we achieved complete resection through single-port thoracoscopy, with only minor haemorrhage, which enabled the patient to recover rapidly. This multidisciplinary collaborative model, based on single-port thoracoscopic surgery, may be of wide practical use for the treatment of mediastinal UCD.

The active forms of STAT5A (signal transducer and activator of transcription 5A) and STAT5B are able to relieve the cytokine dependence of haematopoietic cells and to induce leukaemia in mice. We have demonstrated previously that activation of the PI3K (phosphoinositide 3-kinase) signalling cascade plays a major role in cell growth and survival induced by these proteins. Interaction between STAT5 and p85, the regulatory subunit of the PI3K, has been suggested to be required for this activation. We show in the present study that the scaffolding protein Gab2 [Grb2 (growth-factor-receptor-bound protein 2)-associated binder-2] is an essential component of this interaction. Gab2 is persistently tyrosine-phosphorylated in Ba/F3 cells expressing caSTAT5 (constitutively activated STAT5), independent of JAK2 (Janus kinase 2) activation where it interacts with STAT5, p85 and Grb2, but not with Shp2 [SH2 (Src homology 2)-domain-containing tyrosine phosphatase] proteins. Interaction of STAT5 with Gab2 was also observed in Ba/F3 cells stimulated with interleukin-3 or expressing the oncogenic fusion protein Tel–JAK2. The MAPKs (mitogen-activated protein kinases) ERK1 (extracellular-signal-regulated kinase 1) and ERK2 were constitutively activated in the caSTAT5-expressing cells and were found to be required for caSTAT5-induced cell proliferation. Overexpression of Gab2-3YF, a mutant of Gab2 incapable of binding PI3K, inhibited the proliferation and survival of caSTAT5-expressing cells as well as ERK1/2 and Akt/protein kinase B phosphorylation. Taken together, our results indicate that Gab2 is required for caSTAT5-induced cell proliferation by regulating both the PI3K/Akt and the Ras/MAPK pathways.

The protein tyrosine phosphatase SHP-2 has been proposed to serve as a regulator of leptin signaling, but its specific roles are not fully examined. To directly investigate the role of SHP-2, we employed dominant negative strategies in transfected cells. We show that a catalytically inactive mutant of SHP-2 blocks leptin-stimulated ERK phosphorylation by the long leptin receptor, ObRb. SHP-2, lacking two C-terminal tyrosine residues, partially inhibits ERK phosphorylation. We find similar effects of the SHP-2 mutants after examining stimulation of an ERK-dependentegr-1promoter-construct by leptin. We also demonstrate ERK phosphorylation and egr-1mRNA expression in the hypothalamus by leptin. Analysis of signaling by ObRb lacking intracellular tyrosine residues or by the short leptin receptor, ObRa, enabled us to conclude that two pathways are critical for ERK activation. One pathway does not require the intracellular domain of ObRb, whereas the other pathway requires tyrosine residue 985 of ObRb. The phosphatase activity of SHP-2 is required for both pathways, whereas activation of ERK via Tyr-985 of ObRb also requires tyrosine phosphorylation of SHP-2. SHP-2 is thus a positive regulator of ERK by leptin receptors, and both the adaptor function and the phosphatase activity of SHP-2 are critical for this regulation.

Most, if not all, cytokines activate phosphatidylinositol 3-kinase (PI-3K). Although many cytokine receptors have direct binding sites for the p85 subunit of PI-3K, others, such as the interleukin-3 (IL-3) receptor beta common chain (βc) and the IL-2 receptor beta chain (IL-2Rβ), lack such sites, leaving the mechanism by which they activate PI-3K unclear. Here, we show that the protooncoprotein Shc, which promotes Ras activation by recruiting the Grb2-Sos complex in response to stimulation of cytokine stimulation, also signals to the PI-3K/Akt pathway. Analysis of Y→F and “add-back” mutants of βc shows that Y577, the Shc binding site, is the major site required for Gab2 phosphorylation in response to cytokine stimulation. When fused directly to a mutant form of IL-2Rβ that lacks other cytoplasmic tyrosines, Shc can promote Gab2 tyrosyl phosphorylation. Mutation of the three tyrosyl phosphorylation sites of Shc, which bind Grb2, blocks the ability of the Shc chimera to evoke Gab2 tyrosyl phosphorylation. Overexpression of mutants of Grb2 with inactive SH2 or SH3 domains also blocks cytokine-stimulated Gab2 phosphorylation. The majority of cytokine-stimulated PI-3K activity associates with Gab2, and inducible expression of a Gab2 mutant unable to bind PI-3K markedly impairs IL-3-induced Akt activation and cell growth. Experiments with the chimeric receptors indicate that Shc also signals to the PI-3K/Akt pathway in response to IL-2. Our results suggest that cytokine receptors lacking direct PI-3K binding sites activate Akt via a Shc/Grb2/Gab2/PI-3K pathway, thereby regulating cell survival and/or proliferation.

ABSTRACTMost, if not all, cytokines activate phosphatidylinositol 3-kinase (PI-3K). Although many cytokine receptors have direct binding sites for the p85 subunit of PI-3K, others, such as the interleukin-3 (IL-3) receptor beta common chain (ßc) and the IL-2 receptor beta chain (IL-2Rß), lack such sites, leaving the mechanism by which they activate PI-3K unclear. Here, we show that the protooncoprotein Shc, which promotes Ras activation by recruiting the Grb2-Sos complex in response to stimulation of cytokine stimulation, also signals to the PI-3K/Akt pathway. Analysis of Y?F and “add-back” mutants of ßc shows that Y577, the Shc binding site, is the major site required for Gab2 phosphorylation in response to cytokine stimulation. When fused directly to a mutant form of IL-2Rß that lacks other cytoplasmic tyrosines, Shc can promote Gab2 tyrosyl phosphorylation. Mutation of the three tyrosyl phosphorylation sites of Shc, which bind Grb2, blocks the ability of the Shc chimera to evoke Gab2 tyrosyl phosphorylation. Overexpression of mutants of Grb2 with inactive SH2 or SH3 domains also blocks cytokine-stimulated Gab2 phosphorylation. The majority of cytokine-stimulated PI-3K activity associates with Gab2, and inducible expression of a Gab2 mutant unable to bind PI-3K markedly impairs IL-3-induced Akt activation and cell growth. Experiments with the chimeric receptors indicate that Shc also signals to the PI-3K/Akt pathway in response to IL-2. Our results suggest that cytokine receptors lacking direct PI-3K binding sites activate Akt via a Shc/Grb2/Gab2/PI-3K pathway, thereby regulating cell survival and/or proliferation.

The nontransmembrane protein tyrosine phosphatase SHP-2 plays a critical role in growth factor and cytokine signaling pathways. Previous studies revealed that a fraction of SHP-2 moves to focal contacts upon integrin engagement and that SHP-2 binds to SHP substrate 1 (SHPS-1)/SIRP-1α, a transmembrane glycoprotein with adhesion molecule characteristics (Y. Fujioka et al., Mol. Cell. Biol. 16:6887–6899, 1996; M. Tsuda et al., J. Biol. Chem. 273:13223–13229). Therefore, we asked whether SHP2–SHPS-1 complexes participate in integrin signaling. SHPS-1 tyrosyl phosphorylation increased upon plating of murine fibroblasts onto specific extracellular matrices. Both in vitro and in vivo studies indicate that SHPS-1 tyrosyl phosphorylation is catalyzed by Src family protein tyrosine kinases (PTKs). Overexpression of SHPS-1 in 293 cells potentiated integrin-induced mitogen-activated protein kinase (MAPK) activation, and potentiation required functional SHP-2. To further explore the role of SHP-2 in integrin signaling, we analyzed the responses of SHP-2 exon 3−/−and wild-type cell lines to being plated on fibronectin. Integrin-induced activation of Src family PTKs, tyrosyl phosphorylation of several focal adhesion proteins, MAPK activation, and the ability to spread on fibronectin were defective in SHP-2 mutant fibroblasts but were restored upon SHP-2 expression. Our data suggest a positive-feedback model in which, upon integrin engagement, basal levels of c-Src activity catalyze the tyrosyl phosphorylation of SHPS-1, thereby recruiting SHP-2 to the plasma membrane, where, perhaps by further activating Src PTKs, SHP-2 transduces positive signals for downstream events such as MAPK activation and cell shape changes.

ABSTRACTThe nontransmembrane protein tyrosine phosphatase SHP-2 plays a critical role in growth factor and cytokine signaling pathways. Previous studies revealed that a fraction of SHP-2 moves to focal contacts upon integrin engagement and that SHP-2 binds to SHP substrate 1 (SHPS-1)/SIRP-1a, a transmembrane glycoprotein with adhesion molecule characteristics (Y. Fujioka et al., Mol. Cell. Biol. 16:6887–6899, 1996; M. Tsuda et al., J. Biol. Chem. 273:13223–13229). Therefore, we asked whether SHP2–SHPS-1 complexes participate in integrin signaling. SHPS-1 tyrosyl phosphorylation increased upon plating of murine fibroblasts onto specific extracellular matrices. Both in vitro and in vivo studies indicate that SHPS-1 tyrosyl phosphorylation is catalyzed by Src family protein tyrosine kinases (PTKs). Overexpression of SHPS-1 in 293 cells potentiated integrin-induced mitogen-activated protein kinase (MAPK) activation, and potentiation required functional SHP-2. To further explore the role of SHP-2 in integrin signaling, we analyzed the responses of SHP-2 exon 3-/-and wild-type cell lines to being plated on fibronectin. Integrin-induced activation of Src family PTKs, tyrosyl phosphorylation of several focal adhesion proteins, MAPK activation, and the ability to spread on fibronectin were defective in SHP-2 mutant fibroblasts but were restored upon SHP-2 expression. Our data suggest a positive-feedback model in which, upon integrin engagement, basal levels of c-Src activity catalyze the tyrosyl phosphorylation of SHPS-1, thereby recruiting SHP-2 to the plasma membrane, where, perhaps by further activating Src PTKs, SHP-2 transduces positive signals for downstream events such as MAPK activation and cell shape changes.

V-src-dependent and -independent alterations in the steady-state content, rates of synthesis, and turnover of fibronectin protein and mRNA were identified using rat fibroblasts which are temperature sensitive for p60v-srcactivity. Activation of p60v-srccaused a fivefold reduction in the rate of fibronectin biosynthesis. The v-src-dependent decrease in fibronectin biosynthesis resulted from a similar reduction in the steady-state content of fibronectin mRNA. This change was reversible and required more than 24 h, implying an indirect effect of p60v-srcon fibronectin gene expression. The rate of fibronectin mRNA turnover and pattern of alternative splicing were unchanged following p60v-srcactivation, indicating that these regulatory steps are insensitive to v-srctransformation. A v-src-specific reduction of at least threefold was measured for the rate of fibronectin gene transcription, and gene transfer studies using fibronectin promoter-CAT reporter genes indicated that transcriptional repression occurs at the level of initiation. When p60v-srcwas inactive, CAT reporter genes controlled by 4.9 or 3.2 kb of the rat fibronectin promoter exhibited relatively increased CAT activity (∼twofold) compared to another CAT reporter construction controlled by only 880 bp of the fibronectin promoter. In contrast, CAT activity was relatively reduced (∼twofold) for the reporter constructions containing 4.9 or 3.2 kb of the promoter when p60v-srcwas active. These findings indicate that the distal portion of the fibronectin promoter contains a v-src-sensitive element(s) which mediates a decrease in the rate of fibronectin transcription initiation by negative control.

ABSTRACTThe protein tyrosine phosphatase SHP-1 is a critical regulator of macrophage biology, but its detailed mechanism of action remains largely undefined. SHP-1 associates with a 130-kDa tyrosyl-phosphorylated species (P130) in macrophages, suggesting that P130 might be an SHP-1 regulator and/or substrate. Here we show that P130 consists of two transmembrane glycoproteins, which we identify as PIR-B/p91A and the signal-regulatory protein (SIRP) family member BIT. These proteins also form separate complexes with SHP-2. BIT, but not PIR-B, is in a complex with the colony-stimulating factor 1 receptor (CSF-1R), suggesting that BIT may direct SHP-1 to the CSF-1R. BIT and PIR-B bind preferentially to substrate-trapping mutants of SHP-1 and are hyperphosphorylated in macrophages from motheaten viablemice, which express catalytically impaired forms of SHP-1, indicating that these proteins are SHP-1 substrates. However, BIT and PIR-B are hypophosphorylated in motheatenmacrophages, which completely lack SHP-1 expression. These data suggest a model in which SHP-1 dephosphorylates specific sites on BIT and PIR-B while protecting other sites from dephosphorylation via its SH2 domains. Finally, BIT and PIR-B associate with two tyrosyl phosphoproteins and a tyrosine kinase activity. Tyrosyl phosphorylation of these proteins and the level of the associated kinase activity are increased in the absence of SHP-1. Our data suggest that BIT and PIR-B recruit multiple signaling molecules to receptor complexes, where they are regulated by SHP-1 and/or SHP-2.

ABSTRACTThe protein tyrosine phosphatase SHP-1 is a critical regulator of macrophage biology, but its detailed mechanism of action remains largely undefined. SHP-1 associates with a 130-kDa tyrosyl-phosphorylated species (P130) in macrophages, suggesting that P130 might be an SHP-1 regulator and/or substrate. Here we show that P130 consists of two transmembrane glycoproteins, which we identify as PIR-B/p91A and the signal-regulatory protein (SIRP) family member BIT. These proteins also form separate complexes with SHP-2. BIT, but not PIR-B, is in a complex with the colony-stimulating factor 1 receptor (CSF-1R), suggesting that BIT may direct SHP-1 to the CSF-1R. BIT and PIR-B bind preferentially to substrate-trapping mutants of SHP-1 and are hyperphosphorylated in macrophages from motheaten viablemice, which express catalytically impaired forms of SHP-1, indicating that these proteins are SHP-1 substrates. However, BIT and PIR-B are hypophosphorylated in motheatenmacrophages, which completely lack SHP-1 expression. These data suggest a model in which SHP-1 dephosphorylates specific sites on BIT and PIR-B while protecting other sites from dephosphorylation via its SH2 domains. Finally, BIT and PIR-B associate with two tyrosyl phosphoproteins and a tyrosine kinase activity. Tyrosyl phosphorylation of these proteins and the level of the associated kinase activity are increased in the absence of SHP-1. Our data suggest that BIT and PIR-B recruit multiple signaling molecules to receptor complexes, where they are regulated by SHP-1 and/or SHP-2.

Multiple studies have demonstrated an important role for the Src homology 2-containing tyrosine phosphatase 2 (SHP-2) in receptor tyrosine kinase-regulated cell proliferation and differentiation. Recent studies have identified potential SHP-2 substrates which mediate these effects. SHP-2 also is implicated in several cytokine receptor signaling pathways and in Bcr-Abl transformation. However, its precise role and targets in normal and abnormal hematopoietic cells remain to be determined. We identified two novel tyrosyl-phosphorylated proteins associated with SHP-2 in hematopoietic cells. The first, a 97-kDa cytosolic protein (p97), associates inducibly with SHP-2 upon cytokine stimulation and constitutively in Bcr-Abl-transformed cells. In contrast, p135, a 135-kDa transmembrane glycoprotein, forms a distinct complex with SHP-2, independent of cytokine stimulation or Bcr-Abl transformation. Far Western analysis reveals that SHP-2, via its Src homology 2 domains, can interact directly with either protein. In vitrodephosphorylation experiments, as well as transient transfection studies using wild type and mutant SHP-2 constructs, suggest that p97 and p135 also are SHP-2 substrates. Our results indicate that SHP-2 forms at least two separate complexes in hematopoietic cells and point to new potential SHP-2 targets.

This study analyzes the contribution of large-scale turbulent structures, including very large-scale and large-scale motions, to the streamwise turbulent kinetic energy and momentum flux in comparison with the contribution of the gusty wind disturbances based on the high-quality data obtained from the field measurements conducted in the near-neutral surface layer. The results of this study denote that the gusty wind disturbances contain only a portion of the energy contained in very large-scale motions and do not contain any of the information contained in large-scale motions. The amount of lost contributions to the streamwise turbulent kinetic energy and momentum flux increases linearly with the friction velocity, eventually becoming 53% and 67%, respectively. This indicates that large-scale turbulent structures (very large-scale motions and large-scale motions) better describe the coherent structures in the atmospheric surface layer when compared with the gusty wind disturbances.