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Introduction: Compared to abdominoperineal resection (APR), sphincter preservation using low anterior resection (AR) for rectal cancer (RC) implies the risk of impaired functional outcome and postoperative complications associated with a persistent or additionally required ostomy. The aim of our study was to compare quality of life (QoL) after AR and APR with a special separate analysis of AR patients with a stoma. Methods: QoL of 84 APR, 356 AR, and 29 AR patients with complications and an additional stoma, termed converted therapy (COT) patients, was compared with regard to groups and effect of radiotherapy (RT). All patients received rectal resection between 1998 and 2013, and 47% of the patients had RT. QoL was assessed using extended EORTC QLQ-C30 and -CR38 questionnaires. Results: Questionnaires from 57 APR, 165 AR, and 25 COT patients alive were evaluated after a median time of 4 years after surgery. Global health status was equally high in AR and APR patients (score: 67), whereas COT patients turned out with a significantly lower score of 50 (p = 0.007). Compared to APR and COT, AR patients revealed less symptoms and higher functionality, especially for physical, role, and social functioning (p < 0.001). The reduction of QoL instances was significant in the COT group and in all patients treated by RT. Conclusion: QoL after RC resection may be further improved by avoiding additionally required ostomy after AR but also RT by a better individual selection of qualified patients. Qualification parameters urgently need to be defined by prospective studies.

Leiomyosarcoma (LMS) is characterized by high genomic complexity, and to date, no specific targeted therapy is available. In a genome-wide approach, we profiled genomic aberrations in a small cohort of eight primary tumours, two relapses, and eight metastases across nine different patients. We identified CDK4 amplification as a recurrent alteration in 5 out of 18 samples (27.8%). It has been previously shown that the LMS cell line SK-LMS-1 has a defect in the p16 pathway and that this cell line can be inhibited by the CDK4 and CDK6 inhibitor palbociclib. For SK-LMS-1 we confirm and for SK-UT-1 we show that both LMS cell lines express CDK4 and that, in addition, strong CDK6 expression is seen in SK-LMS-1, whereas Rb was expressed in SK-LMS-1 but not in SK-UT-1. We confirm that inhibition of SK-LMS-1 with palbociclib led to a strong decrease in protein levels of Phospho-Rb (Ser780), a decreased cell proliferation, and G0/G1-phase arrest with decreased S/G2fractions. SK-UT-1 did not respond to palbociclib inhibition. To compare thesein vitrofindings with patient tissue samples, a p16, CDK4, CDK6, and p-Rb immunohistochemical staining assay of a large LMS cohort (n=99patients with 159 samples) was performed assigning a potential responder phenotype to each patient, which we identified in 29 out of 99 (29.3%) patients. Taken together, these data show that CDK4/6 inhibitors may offer a new option for targeted therapy in a subset of LMS patients.

Introduction and importance Unclear retroperitoneal tumors impose major challenges for clinicians. Tumors can originate primarily from retroperitoneal tissue or secondarily invade into the retroperitoneum. While benign lesions also occur, malignant tumors are far more common. Clinical presentation depends on replacement or invasion of other organs and is therefore highly variable. The heterogeneous tumor composition makes a definitive preoperative diagnosis difficult. Surgical resection is the gold standard for treatment but often proves challenging due to frequent involvement of large retroperitoneal vessels. Case presentation We present the case of a 70-year old woman diagnosed with a large, unclear retroperitoneal tumor. Initial clinical symptoms were increasing dyspnea and dysphagia in our clinic. Gastroenterologic and cardiologic workup was unremarkable. Computed Tomography (CT) revealed a large retroperitoneal mass in the right upper abdomen with severe displacement of the inferior vena cava and renal veins. The patient was scheduled for primary tumor resection. The procedure was challenging due to the vessel involvement and large blood pressure alterations during tumor mobilization. The post-op pathologic workup then revealed the rare finding of a completely resected paraganglioma. The post-surgical course was uneventful. One year after diagnosis, the patient is relapse-free. Clinical discussion Among retroperitoneal tumors, paragangliomas and pheochromocytomas are rare tumor entities. Asymptomatic, sporadic disease is hard to identify preoperatively and can cause unexpected complications in the OR. An experienced team is crucial in achieving best short- and long-term outcomes. Conclusion This case impressively shows the challenges of retroperitoneal tumors and the importance of interdisciplinary work in these cases., Highlights • Retroperitoneal tumors show high variability in origin and clinical presentation. • Diagnosis and treatment of unclear retroperitoneal tumors remain challenging. • Endocrinologically silent tumors can cause serious intraoperative adverse effects. • Clinical management of these cases requires close interdisciplinary work. • Case report of one of the largest paragangliomas reported with complex vessel involvement

Colorectal cancer (CRC) is the third most common cancer worldwide. A diagnosis at early stages with enhanced screening methods is vital as metastases and recurrences increase mortality. The aim of this study was to analyze the tumor markers CEA and CA19-9 combined in correlation with diagnostics and prognosis. Therefore, 1487 patients with CRC who were diagnosed and treated between 2000 and 2015 at the University Hospital Ulm, Germany, were retrospectively evaluated. Overall and recurrence-free survival was analyzed in association with preoperative CEA and CA19-9 separately and combined and a multivariate analysis was performed. The 5-year overall survival was significantly shorter in patients with a CEA or CA19-9 level ≥200 compared to patients with an increased, but &lt, 200, or normal level (CEA: 69%/44%/7%, CA19-9: 66%/38%/8%). Patients with both tumor markers increased also showed a remarkably shorter 5-year survival rate (CEA+/CA19-9+: 23%). The multivariate analysis emphasizes these results (p-value &lt, 0.0001). Patients with both tumor markers elevated had the shortest 5-year recurrence-free survival rate, followed by patients with either CEA or CA19-9 elevated (CEA-/CA19-9-: 79%, CEA+/CA19-9, CEA-/CA19-9+: 65%, CEA+/CA19-9+: 44%). In conclusion, measuring CEA and CA19-9 preoperatively in CRC patients is reasonable and could be useful as a prognostic factor.

Regression models are frequently used to model the functional relationship between an interesting outcome parameter and one or more potentially relevant explanatory variables. Objectives can be to set up as a prognostic model, for example, or an estimation model for a certain parameter of interest. Determining half-life periods can be viewed as a particular application of such an estimation model. However, specific to these modelling problems is that time-dependent active agent concentrations can be nonlinear. Concurrently, a major limitation to common regression approaches is the assumed linear relation of the investigated variables. Therefore, a more flexible approach is required to handle the problem of finding a model which fits the data adequately. One possibility is the use of fractional polynomials. The application of this modelling approach in a univariate setting is proposed in order to have an appropriate data model which subsequently serves as an estimation model for half-life periods. This estimation model includes Ridders’ method which is based on a regula falsi approach, a standard methodology of numerical analysis. The suggested procedure is applied to real data examples of antibiotic tissue concentrations in visceral surgery, nephropharmacology and clinical pharmacology and is furthermore compared to simple approaches of modelling nonlinear data.

S100 proteins are widely expressed small molecular EF-hand calcium-binding proteins of vertebrates, which are involved in numerous cellular processes, such as Ca2+ homeostasis, proliferation, apoptosis, differentiation, and inflammation. Although the complex network of S100 signalling is by far not fully deciphered, several S100 family members could be linked to a variety of diseases, such as inflammatory disorders, neurological diseases, and also cancer. The research of the past decades revealed that S100 proteins play a crucial role in the development and progression of many cancer types, such as breast cancer, lung cancer, and melanoma. Hence, S100 family members have also been shown to be promising diagnostic markers and possible novel targets for therapy. However, the current knowledge of S100 proteins is limited and more attention to this unique group of proteins is needed. Therefore, this review article summarises S100 proteins and their relation in different cancer types, while also providing an overview of novel therapeutic strategies for targeting S100 proteins for cancer treatment.

The pharmacokinetics (PK) of β-lactam antibiotics in cystic fibrosis (CF) patients has been compared with that in healthy volunteers for over four decades; however, no quantitative models exist that explain the PK differences between CF patients and healthy volunteers in older and newer studies. Our aims were to critically evaluate these studies and explain the PK differences between CF patients and healthy volunteers. We reviewed all 16 studies that compared the PK of β-lactams between CF patients and healthy volunteers within the same study. Analysis of covariance (ANCOVA) models were developed. In four early studies that compared adolescent, lean CF patients with adult healthy volunteers, clearance (CL) in CF divided by that in healthy volunteers was 1.72 ± 0.90 (average ± standard deviation); in four additional studies comparing age-matched (primarily adult) CF patients with healthy volunteers, this ratio was 1.46 ± 0.16. The CL ratio was 1.15 ± 0.11 in all eight studies that compared CF patients and healthy volunteers who were matched in age, body size and body composition, or that employed allometric scaling by lean body mass (LBM). Volume of distribution was similar between subject groups after scaling by body size. For highly protein-bound β-lactams, the unbound fraction was up to 2.07-fold higher in older studies that compared presumably sicker CF patients with healthy volunteers. These protein-binding differences explained over half of the variance for the CL ratio (p

Meropenem serves as a clinically important, broad-spectrum antibiotic. While meropenem is commonly used in obese patients, its pharmacokinetics in this patient group is not well known. Our aim was to characterize the population pharmacokinetics and target attainment in plasma, subcutaneous tissue, and peritoneal fluid for meropenem in morbidly obese patients. Four doses of 1g meropenem were given as 15-min infusions every 8 h to five morbidly obese patients (body mass index [BMI], 47.6 to 62.3 kg/m 2 ). After the fourth dose, serial meropenem concentrations were determined in plasma and, via microdialysis, in subcutaneous tissue and peritoneal fluid. All concentrations were analyzed simultaneously via population modeling, and target attainment probabilities predicted via Monte Carlo simulations using the target of unbound meropenem concentrations above the MIC for at least 40% of the dosing interval. For patients with 53 kg fat-free mass, total clearance was 18.7 liters/h and volume of distribution at steady state was 27.6 liters. The concentrations in subcutaneous tissue and peritoneal fluid largely paralleled those in plasma (equilibration half-life, 90% after 1 g meropenem every 8 h as a 15-min infusion for MICs of up to 2 mg/liter in plasma and peritoneal fluid and 0.5 mg/liter in subcutaneous tissue. Meropenem pharmacokinetics in plasma and peritoneal fluid of obese patients was predictable, but subcutaneous tissue penetration varied greatly. (This study has been registered at ClinicalTrials.gov under registration no. NCT01407965.)

Ertapenem provides broad-spectrum activity against many pathogens, and its use is relevant for the prophylaxis and treatment of infections in morbidly obese patients undergoing surgery. However, its pharmacokinetics and tissue penetration in these patients are not well defined. We assessed the population pharmacokinetics and target attainment for ertapenem in the plasma, subcutaneous tissue, and peritoneal fluid of morbidly obese patients. Six female patients (body mass index, 43.7 to 55.9 kg/m 2 ) received 1,000 mg ertapenem as 15-min infusions at 0 and 26 h. On day 2, the unbound ertapenem concentrations in plasma, subcutaneous tissue, and peritoneal fluid were measured by microdialysis; total plasma concentrations were additionally quantified. The probability of attaining a target of an unbound ertapenem concentration above the MIC for at least 40% of the dosing interval was predicted via Monte Carlo simulations. The population pharmacokinetic model contained two disposition compartments and simultaneously described all concentrations. For unbound ertapenem, total clearance was 12.3 liters/h (coefficient of variation, 21.6% for between-patient variability) and the volume of distribution at steady state was 57.8 liters in patients with a 53-kg fat-free mass. The area under the concentration-time curve (AUC) for ertapenem was 49% lower in subcutaneous tissue and 25% lower in peritoneal fluid than the unbound AUC in plasma. Tissue penetration was rapid (equilibration half-life, 90%) target attainment probabilities for MICs of up to 1 mg/liter in plasma, 0.25 to 0.5 mg/liter in subcutaneous tissue, and 0.5 mg/liter in peritoneal fluid. Ertapenem presents an attractive choice for many pathogens relevant to morbidly obese patients undergoing surgery. (This study has been registered at ClinicalTrials.gov under identifier NCT01407965.)

Objectives Minimally invasive surgery and minimal access surgery has replaced conventional surgical procedures during the last 15 years with benefits including a decrease in postoperative pain, time spent convalescing, early return to normal activities, and pleasing cosmetic results. Many centers perform kidney transplant through an oblique or J-shaped approach deep into the iliac fossa. Both approaches have possible disadvantages regarding the extent of tissue trauma. Therefore, we introduced a new minimal access kidney transplant technique in our kidney transplant program in 2008 and report the outcomes of the first 10 patients transplanted with this technique. Materials and methods Between November 2008 to May 2009, ten kidney recipients were subjected to the minimal access kidney transplant technique. These patients represent a consecutive series of kidney transplants performed by the senior surgeon or under the supervision of the senior surgeon of transplant surgery. Results The mean (± SD) age of the recipients was 47 ± 14.7 years (range, 28-67 y), the body mass index was 25 ± 2.02 (range, 23-30), the time of procedure was 126.2 ± 27.5 minutes (range, 90-165 min) with a mean (± SD) anastomoses time of 27.7 ± 8.4 minutes (range, 19-45 min). Follow-up for all recipients was at least 18 months. There was no reintervention necessary, no wound infections, no primary nonfunction or a delayed graft function, no need for dialysis, no acute rejection episodes, no graft loss, no wound dehiscence, no incisional hernia, or lymphocele. Furthermore, no urologic complications or vascular complications were observed. Conclusions Our reported technique was used on heart-beating donor kidneys as well as on living-donor organs and is safe with less comorbidity. This minimal access kidney transplant technique might be an alternative procedure for avoiding some of the disadvantages of conventional approaches used for kidney transplant.

The incidence of acute pancreatitis varies from 5 to 80 per 100,000 throughout the world. The most common cause of death in these patients is infection of pancreatic necrosis by enteric bacteria, spurring the discussion of whether or not prophylactic antibiotic administration could be a beneficial approach. In order to provide evidence of the effect of antibiotic prophylaxis in severe acute pancreatitis (SAP) we performed an updated systematic review and meta-analysis on this topic.The review of randomized controlled trials was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. We conducted a search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. For assessment of the treatment effects we calculated the risk ratios (RRs) for dichotomous data of included studies.Fourteen trials were included with a total of 841 patients. The use of antibiotic prophylaxis was not associated with a statistically significant reduction in mortality (RR 0.74 [95% CI 0.50-1.07]), in the incidence of infected pancreatic necrosis (RR 0.78 [95% CI 0.60-1.02]), in the incidence of non-pancreatic infections (RR 0.70 [95% CI 0.46-1.06]), and in surgical interventions (RR 0.93 [95% CI 0.72-1.20]).In summary, to date there is no evidence that supports the routine use of antibiotic prophylaxis in patients with SAP.

The members of the casein kinase 1 (CK1) family are highly conserved and are expressed in many eukaryotes ranging from yeast to humans. Mammalian CK1 isoforms (alpha, beta, gamma, delta, epsilon) and their splice variants are involved in diverse cellular processes including membrane trafficking, circadian rhythm, cell cycle progression, chromosome segregation, apoptosis and cellular differentiation. Mutations and deregulation of CK1 expression and activity has been linked to various diseases including neurodegenerative disorders such as Alzheimer's and Parkinson's disease, sleeping disorders and proliferative diseases such as cancer. In this review, we summarize the functions of CK1 and outline the participation of CK1 in signal transduction pathways linked to cancer development.

Body packing is a well recognized method of drug trafficking by smuggling drug containers in the gastrointestinal tract. Medical professionals might get involved with body packers after presentation by law enforcement or in case of medical emergencies such as drug overdose or mechanical intestinal obstruction due to the containers within the gastrointestinal tract. Besides the medical aspects in treating these patients, physicians must be aware of all the different legal specifics in dealing with body packers. In case of medical emergencies, drug traffickers have the legal status of regular patients with respect to professional medical discretion. The question remains of what physicians should do with the drugs after surgical removal? Even though the body packer remains the legal owner of the drugs, physicians may not return the drugs, since that constitutes the criminal offence of dealing in narcotics. Returning the drugs to law enforcement authorities is also prohibited because of professional medical discretion. The only way out of this predicament is for physicians to destroy the drugs under the observation of witnesses.

Benign cystic teratoma of the pancreas often appears to be potentially malignant in preoperative staging. The final diagnosis is generally obtained after surgical removal. Reliable prediction is mandatory for differential treatment.A Medline query was performed for the terms cystic teratoma, dermoid cyst and pancreas. Data were analyzed for patient characteristics, clinical appearance, diagnostic findings, therapy and follow-up.Including our own, 26 cases of pancreatic cystic teratoma were identified. The majority of patients were symptomatic by unspecific gastrointestinal complaints. Up to date, imaging techniques fail at a distinct preoperative diagnosis. Surgical treatment evolved from various drainage and excision procedures into radical resection.Despite the strictly benign nature of cystic teratoma, oncologic resection is mostly inevitable due to difficult preoperative diagnosis. No reliable predictive marker was found to allow for organ- or parenchyma-preserving procedures. Therefore, surgery remains the treatment of choice to exclude malignancy.

Background: There are only limited data on tissue kinetics of ertapenem in colorectal tissue more than 3 h after administration of the drug. The purpose of this study was to assess the pharmacokinetics (PK) of ertapenem in colorectal tissue via population PK modeling. Patients and Methods: Patients ���18 years requiring surgical intervention at the colon and/or rectum were eligible (ClinicalTrials.gov identifier: NCT 00535652). Tissue and blood samples were taken during surgery after a single dose of 1 g ertapenem. Ertapenem concentration was determined by high-performance liquid chromatography/mass spectrometry. Population PK modeling was performed in S-ADAPT. Results: Twenty-three patients were enrolled. The highest tissue concentration was 6.4 �� 2.3 mg/kg, the highest total plasma concentration 51.34 �� 9.4 mg/l, the highest unbound plasma concentration 7.05 �� 1.1 mg/l, and the unbound fraction in plasma was 14���15% for total ertapenem concentrations below approximately 22 mg/l, 19% at 100 mg/l, and 25% at 250 mg/l. The estimated geometric mean terminal half-life was 2.5 h for plasma and tissue. In the Monte Carlo simulation, a single dose of 1,000 mg ertapenem achieved robust (���90%) probabilities of target attainment up to a minimum inhibitory concentration (MIC) of approximately 2 mg/l for the bacteriostasis target (free time above MIC, fT>MIC = 20%) and up to 0.25���0.5 mg/l for the near-maximal killing target (40% fT>MIC). Conclusion: Our data indicate an adequate penetration of ertapenem into uninfected colorectal tissue up to 8.5 h (35% of the dosing interval) after administration of 1 g intravenously. �� In Copyright http://rightsstatements.org/vocab/InC/1.0/, publishedVersion

The incidence of acute pancreatitis varies from 5 to 80 per 100,000 inhabitants throughout the world. Recognizing the natural course of severe acute pancreatitis a multidisciplinary approach had become the standard. The strategy of postponing surgical intervention was implemented in the treatment algorithm several years ago.A retrospective analysis of patient data from two five-year periods. The first period was from 01/1992 to 12/1997 (group 1), the second period from 10/2001 to 12/2006 (group 2).In this study, we retrospectively analyzed the impact of this approach on the outcome of our patients with necrotizing pancreatitis. The time interval between onset of disease and first necrosectomy was in the mean 19.5 days in patients of group 1 and 30 days in group 2 (p = 0.015). In group 1, 45/78 patients (57%) were operated on during the first 14 days compared to 8/32 patients (25%; p = 0.002) in group 2. The mortality was 41% in group 1 and 18% in group 2 (p = 0.026). There was also a statistically significant decrease in mortality when first necrosectomy was postponed after day 29 (p = 0.015).Our results are in line with several other analyses suggesting that the strategy of postponing surgery in patients with necrotizing pancreatitis is associated with a decreased mortality.

The incidence of acute pancreatitis varies from 5 to 80 per 100,000 inhabitants throughout the world. The most common cause of death in these patients is infection of pancreatic necrosis by enteric bacteria, spurring the discussion of whether or not prophylactic antibiotic administration could be a beneficial approach. We therefore analyzed randomized clinical trials, which form the basis of guidelines and recommendations on this topic.One trial demonstrated that antibiotic prophylaxis reduces mortality, but the statistical design of this trial was questionable. Another important trial, showing an effect of antibiotic prophylaxis on the incidence of pancreatic sepsis, used the wrong statistical test to analyze their data. An analysis with the correct test could not confirm this effect. Three randomized clinical trials demonstrated that antibiotic prophylaxis in severe acute pancreatitis could reduce the incidence of extrapancreatic infections. Two trials showed a significant reduction of the overall infection rate; while in one of them peripancreatic and extrapancreatic infections alone were not significantly different. Two double blinded studies could not demonstrate a significant effect of antibiotic prophylaxis on pancreatic/peripancreatic infection, extrapancreatic infection or mortality.Our analysis shows that some of the reported significant effects of prophylactic antibiotic treatment are either questionable or less clinically relevant. With regards to reduction in mortality and the incidence of infected pancreatic necrosis, no convincing evidence exists which supports the routine administration of prophylactic antibiotics in severe acute pancreatitis.

Objectives: Ertapenem, a class I carbapenem, is approved for the treatment of mild to severe intraabdominal infections, but its in vivo concentrations in intraabdominal tissues are unknown. The purpose of this study was to determine the concentration of ertapenem in intraabdominal tissue. Patients and methods: After informed consent 48 patients, 23 female and 25 male with a median age of 58 years (34–81), requiring surgical intervention at intraabdominal organs were enrolled. Patients received 1 g of ertapenem intravenously for perioperative prophylaxis. Tissue samples were taken after resection of parts of the organs. Plasma samples were taken when tissue samples were taken. Drug concentrations were determined by liquid chromatography/mass spectrometry. An ANCOVA test (analysis of covariance) was performed to assess organ-specific differences in ertapenem concentration and penetration ratios. Results: Mean – SD ertapenem tissue concentration (mg/kg) was 16.0 – 8.8 in the gall bladder, 12.1 – 5.3 in the colon, 7.0 – 5.7 in the small bowel, 4.5 – 2.3 in the liver and 3.4 – 2.9 in the pancreas. The mean tissue/plasma ratio was 0.19 (colon), 0.17 (small bowel), 0.17 (gall bladder), 0.088 (liver) and 0.095 (pancreas). The ANCOVA test revealed statistically significant organ-specific differences in ertapenem tissue concentration in the gall bladder versus liver/pancreas and in tissue penetration for the colon versus liver/pancreas. Conclusions: These pharmacokinetic results support the assumption that ertapenem is suitable for the treatment of intraabdominal infections.

Background: Members of the casein kinase 1 family of serine/threonine specific kinases are highly conserved from yeast to mammals and seem to play an important role in vesicular trafficking, DNA repair, cell cycle progression and cytokinesis. The CK1 isoform delta (CK1δ) has been shown to be involved in the regulation of microtubule dynamics, since CK1δ specifically interacts with microtubules and the spindle apparatus. Furthermore, CK1δ phosphorylates α/β tubulin itself as well as several microtubule-associated proteins (MAPs) in vitro and in vivo. To characterize the functions of CK1δ in detail it is important to identify new interaction partners. Methods: We screened a human bone marrow cDNA library from Clontech with a mtCK1δ as bait protein. MAP1A/LC2 was identified as a new interacting partner of CK1δ by sequencing of the cDNA insert of a plasmid (coding for last 176 aa of LC2) isolated from a positive clone. A series of truncated fragments of both, LC2-P16 and CK1δ, were constructed in order to determine the domains of LC2 and CK1δ respectively being responsible for the interaction. Subsequently, all fragments were tested in the yeast two-hybrid system (YTH). To confirm the interaction between both proteins IP-Western analysis were performed from F111 cell extracts. Several purified truncated GST-LC2-P16 fragments were used as substrates for CK1δ in vitro kinase assays. To obtain further information about the CK1δ specific phosphorylation sites of LC2, tryptic phosphopeptides of the highly phosphorylated GST-LC2 fusion protein GST-LC2-P16 were analyzed by two dimensional phosphopeptide analysis. Results: We have identified a 176 amino acid residue (aa) fragment of the light chain LC2 of MAP1A which specifically interacts with CK1δ in the yeast two-hybrid system. The CK1δ interacting domains on the 176 aa fragment of LC2 are located between aa 2629-aa 2753 and between aa 2754-2805, whereas the two CK1δ regions necessary for the interaction with the LC2 fragment have been identified within the kinase domain between aa 75-100 and between aa 350-375 of the C-terminal domain of CK1δ. The interaction between CK1δ to LC2 in higher eucaryontic cells could be confirmed in IP-Western analysis. Furthermore, LC2 has been identified as a new substrate of CK1δ and the phosphorylation sites have been mapped by 2D phosphopeptide analysis. Conclusion: We propose a model in which CK1δ might be able to modulate microtubule dynamics by changing the phosphorylation status of the light chain LC2 of MAP1A.

CK1delta, a member of the casein kinase 1 family of serine/threonine specific kinases, has been shown to be involved in the regulation of microtubule dynamics. We have now identified a 176 aa fragment of the light chain LC2 of MAP1A (termed LC2-P16) specifically interacting with CK1delta. Two CK1delta interacting domains of LC2 were identified, located between aa 2629 and 2753 close to aa 2683 and between aa 2712 and 2805 of LC2. The two regions necessary for the interaction of LC2 with CK1delta have been mapped between aa 76-103 and aa 351-375 of CK1delta. Furthermore, LC2 has been identified as a new substrate of CK1delta. We therefore propose a model in which CK1delta could modulate microtubule dynamics by changing the phosphorylation status of the light chain LC2 of MAP1A.