MYOTUBULARIN RELATED - 2 REGULATES RECEPTOR MEDIATED ENDOCYTOSIS - 8, A NOVEL PI (3) P BINDING PROTEIN THAT CONTROLS EARLY ENDOSOMAL CLATHRIN DYNAMICS AND ENDOSOMAL RETROGRADE TRANSPORT PATHWAY THROUGH ITS N-TERMINAL PHOSPHOINOSITIDE BINDING MOTIF

Myotubularin related protein 2 (MTMR2) is a member of the myotubularin family of phosphoinositide lipid phosphatases whose subcellular localization is regulated by a phosphorylation event on Ser 58. Our laboratory has shown that the phosphorylationmimetic mutant (S58E) targets MTMR2 to the cytoplasm, whereas the phosphorylationdeficient variant MTMR2 (S58A) targets it to Rab5-positive endosomes resulting in PI(3)P depletion. Although MTMR2 dephosphorylates PI(3)P and PI(3,5)P2, the phosphoinositide binding proteins that are regulated by MTMR2 are poorly characterized. In this study, we identified RME-8 as a novel PI(3)P binding protein implicated in the translocation of Hsc70 to early endosomes for clathrin removal during retrograde transport. Remarkably, the depletion of PI(3)P by MTMR2 S58A attenuated RME-8 endosomal localization. Moreover, we have identified the amino acid determinants required for PI(3)P binding within a region predicted to adopt a pleckstrin homology-like fold in the N terminus of RME-8. The ability of RME-8 to associate with PI(3)P and early endosomes is largely abolished when residues Lys17, Trp20, Tyr24, or Arg26 are mutated resulting in diffuse cytoplasmic localization of RME-8 while maintaining the ability to interact with Hsc70. We also provide evidence that RME-8 PI(3)P binding regulates the early endosomal clathrin dynamics and alters the steady state localization of the cation independent mannose 6-phosphate receptor. In addition, once a phosphorylation-deficient variant (S58A) targets MTMR2 to Rab5-positive endosomes and depleting PI(3)P, it results in increased endosomal signaling, such as a significant increase in ERK1/2 activation. Using in vitro kinase assays, cellular MAPK inhibitors, siRNA knockdown and a phosphospecific-Ser58 antibody, we provide evidence that ERK1/2 is the kinase responsible for phosphorylating MTMR2 at position Ser58, which suggests that the endosomal targeting of MTMR2 is regulated through an ERK1/2 negative feedback mechanism. Taken together, our results suggest a model in which the localization of RME-8 to endosomal compartments is spatially mediated by PI(3)P binding and temporally regulated by MTMR2 activity and compartmentalization of MTMR2 and potential subsequent effects on endosome maturation and endosome signaling are dynamically regulated through MAPK-mediated differential phosphorylation events

Uncommon acquired Gerbode defect following extensive bicuspid aortic valve endocarditis

Gerbode defect is a rare type of left ventricle to right atrium shunt. It is usually congenital in origin, but acquired cases are also described, mainly following infective endocarditis, valve replacement, trauma or acute myocardial infarction. We report a case of a 50-year-old man who suffered an extensive and complex infective endocarditis involving a bicuspid aortic valve, the mitral-aortic intervalvular fibrosa and the anterior leaflet of the mitral valve. After dual valve replacement and annular reconstruction, a shunt between the left ventricle and the right atrium - Gerbode defect, and a severe leak of the mitral prosthesis were detected. Reintervention was performed with successful shunt closure with an autologous pericardial patch and paravalvular leak correction. No major complications occurred denying the immediate post-surgery period and the follow-up at the first year was uneventful

Strategy for tumor selective disruption of androgen receptor function in the spectrum of prostate cancer

Purpose: Testosterone suppression in prostate cancer (PC) is limited by serious side effects and resistance via restoration of androgen receptor (AR) functionality. ELK1 is required for ARdependent growth in various hormone-dependent and castration resistant PC models. The amino terminal domain of AR docks at two sites on ELK1 to co-activate essential growth genes. This study explores the ability of small molecules to disrupt the ELK1-AR interaction in the spectrum of PC, inhibiting AR activity in a manner that would predict functional tumor selectivity. Experimental design: Small molecule drug discovery and extensive biological characterization of a lead compound. Results: We have discovered a lead molecule (KCI807) that selectively disrupts ELK1-dependent promoter activation by wild-type and variant ARs without interfering with ELK1 activation by ERK. KCI807 has an obligatory flavone scaffold and functional hydroxyl groups on C5 and C3'. KCI807 binds to AR, blocking ELK1 binding, and selectively blocks recruitment of AR to chromatin by ELK1. KCI807 primarily affects a subset of AR target growth genes selectively suppressing AR-dependent growth of PC cell lines with a better inhibitory profile than enzalutamide. KCI807 also inhibits in vivo growth of castration/enzalutamide-resistant cell line-derived and patient-derived tumor xenografts. In the rodent model, KCI807 has a plasma half-life of 6h and maintenance of its antitumor effect is limited by self-induced metabolism at its 3'-hydroxyl. Conclusions: The results offer a mechanism-based therapeutic paradigm for disrupting the AR growth-promoting axis in the spectrum of prostate tumors while reducing global suppression of testosterone actions. KCI807 offers a good lead molecule for drug development

What can be the Role of Public-Private Partnerships and the role of the Collective Action in Ensuring Sustainable Smallholder Participation in High Value Fruit and Vegetable Supply Chains in Albania?

ABSTRACT: Albania is a Mediterranean country where fruits and vegetables occupy an important place in the cropping systems practiced by the Albanian farms but also in the food consumption of the population. Today, the fruits and vegetables growers in Albania have low production capacity and difficulties in selling their products on national and regional market. These poor producers face problems of how to produce safe food (World Bank 2007), be recognized as producing safe food, identify cost-effective technologies for reducing risk, and be competitive with larger producers with advantage of economies of scale in compliance with food safety requirements. In enabling the smallholders to remain competitive in such a system, new institutional arrangements are required. The new and emerging food system (dominated by domestic urban market and export markets, regional competitiveness, globalization, etc.) with high demands for compliance with food safety and traceability disfavor the smallholders due to high coordination costs. The problem is exacerbated by geographic dispersion, low education, and poor access to capital and informatio

Gerbode defect following endocarditis and misinterpreted as severe pulmonary arterial hypertension

<p>Abstract</p> <p>A Gerbode -type defect is a ventricular septal defect communicating directly between the left ventricle and right atrium. It is usually congenital, but rarely is acquired, as a complication of endocarditis. This can be anatomically possible because the normal tricuspid valve is more apically displaced than the mitral valve. However, identification of an actual communication is often extremely difficult, so a careful and meticulous echocardiogram should be done in order to prevent echocardiographic misinterpretation of this defect as pulmonary arterial hypertension. The large systolic pressure gradient between the left ventricle and the right atrium would expectedly result in a high velocity systolic Doppler flow signal in right atrium and it can be sometimes mistakably diagnosed as tricuspid regurgitant jet simulating pulmonary arterial hypertension.</p> <p>We present a rare case of young woman, with endocarditis who presented with severe pulmonary arterial hypertension. The preoperative diagnosis of left ventricle to right atrial communication (acquired Gerbode defect) was suspected initially by echocardiogram and confirmed at the time of the surgery.</p> <p>A point of interest, apart from the diagnostic problem, was the explanation for its mechanism and presentation. The probability of a bacterial etiology of the defect is high in this case.</p