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

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

Evidence for behavioral preference toward environmental concentrations of urban-use herbicides in a model adult fish

Fish live in waters of contaminant flux. In three urban, fish-bearing waterways of British Columbia, Canada, we found the active ingredients of WeedEx®, KillEx®, and Roundup® herbicide formulations (2,4-D, dicamba, glyphosate, and mecoprop) at low to high ng/L concentrations (0.26 to 309 ng/L) in routine conditions, i.e., no rain for at least one week. Following rain, these concentrations increased by an average of eightfold, suggesting runoff as a major route of herbicide introduction in these waterways. To determine whether fish might be able to limit point-source exposures through sensory-driven behaviors, we introduced pulses of representative herbicide mixtures to individual adult zebrafish (a model species) in flow-through tanks. Fish did the opposite of limit exposure; they chose to spend more time in pulses of herbicide mixtures representative of those that may occur with rain events. This attraction response was not altered by a previous 4-d exposure to lower concentrations of the mixtures, suggesting fish will not learn from previous exposures. However, previous exposures did alter an attraction response to an amino acid prevalent in food (L-alanine). The present study demonstrates that fish living within urban waterways may elect to place themselves in herbicide-contaminated environments and that these exposures may alter their behavioral responses to cues necessary for survival.Environ. Toxicol. Chem. 2011;30:2046–2054. © 2011 SETA

COVID-19: A Systematic Review of the Transmissibility, Pathogenesis, Entry Factors, and Signature Immune Response

Objectives: The emergence of coronavirus disease 2019 (COVID-19), caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global health calamity unprecedented in the modern world. The disease spread worldwide, and to date, there have been over 230 million confirmed cases of COVID-19, including approximately 4.7 million deaths. Mutant variants of the virus have raised concerns about additional pandemic waves and threaten to reverse our progress thus far to limit the spread of the virus. These variants include Alpha, Beta, and Delta (first reported in December 2020 in the United Kingdom, South Africa, and India, respectively) and Gamma (reported in January 2021 in Brazil). In some cases, countries have even reported a rise in daily cases higher than the first wave in March 2020. Given the rapidly evolving nature of COVID-19 and subsequent new findings and updates each day, this review article aims to comprehensively summarize the etiology, pathophysiology, and clinical features of SARS-CoV-2 infection. Methods: A systematic review of the literature was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to gain insight into the transmissibility, pathogenesis, entry factors, and immune response of COVID-19. Specifically, Pubmed and Google Scholar databases were searched to identify any relevant articles. References within the included articles were reviewed. Published articles related to search criteria from the onset of the COVID-19 pandemic to March 2022 were included. Results: Viral transmissibility is predominantly affected by the modes of transmission, various mutations on the nucleocapsid protein and endoRNAse, gender, age, and other factors. The pathophysiological mechanism is generally unknown, although the clinical manifestations such as headache, loss of smell and taste, vomiting, diarrhea, multiorgan failure, and dermatological and cardiovascular complications are well documented. The progression of infection depends on the immunopathological response and the innate/adaptive immunity. Conclusion: Our review has summarized the latest knowledge about SARS-CoV2. However, as the pandemic continues to spread across the continents, there is an urgent need for more research on potentially emerging coronaviruses and the development of a universal coronaviruses vaccine to put the pandemic behind us