FSHIP2 regulates epithelial cell polarity through its lipid product,which binds to Dlg1, a pathway subverted by hepatitis C virus core protein

The main targets of hepatitis C virus (HCV) are hepatocytes, the highly polarized cells of the liver, and all the steps of its life cycle are tightly dependent on host lipid metabolism. The interplay between polarity and lipid metabolism in HCV infection has been poorly investigated. Signaling lipids, such as phosphoinositides (PIs), play a vital role in polarity, which depends on the distribution and expression of PI kinases and PI phosphatases. In this study, we report that HCV core protein, expressed in Huh7 and Madin–Darby canine kidney (MDCK) cells, disrupts apicobasal polarity. This is associated with decreased expression of the polarity protein Dlg1 and the PI phosphatase SHIP2, which converts phosphatidylinositol 3,4,5-trisphosphate into phosphatidylinositol 4,5-bisphosphate (PtdIns(3,4)P2). SHIP2 is mainly localized at the basolateral membrane of polarized MDCK cells. In addition, PtdIns(3,4)P2 is able to bind to Dlg1. SHIP2 small interfering RNA or its catalytically dead mutant disrupts apicobasal polarity, similar to HCV core. In core-expressing cells, RhoA activity is inhibited, whereas Rac1 is activated. Of interest, SHIP2 expression rescues polarity, RhoA activation, and restricted core level in MDCK cells. We conclude that SHIP2 is an important regulator of polarity, which is subverted by HCV in epithelial cells. It is suggested that SHIP2 could be a promising target for anti-HCV treatment.     

Cyclic strain promotes shuttling of PYK2/Hic-5 complex from focal contacts in osteoblast-like cells

We showed that cyclic strain (CS) of osteoblastic cells induced tyrosine phosphorylation of two homologous tyrosine kinases FAK and PYK2, and of two homologous adaptor proteins paxillin and Hic5, with similar kinetics. Immunostaining showed that all four proteins were localized to focal contacts in controls. In contrast, the dynamics of their subcellular localization observed after CS differed. While FAK and paxillin remained at the focal contact, Hic-5 and PYK2 translocated outside ventral focal contacts as early as 30 min after CS and were sequestered by the cytoskeleton. Co-immunoprecipitation showed that the association of PYK2/Hic-5 and PYK2/FAK increased with time after strain while that of paxillin and Hic-5 decreased. Altogether these results suggested that CS regulates focal contact activity in osteoblasts by modulating PYK2-containing complexes in particular by shuttling out of the focal contact the adaptor Hic-5 and favoring the anchorage of FAK within contacts.     

Experimental test of the ecosystem impacts of the keystone predator Triops cancriformis (Branchiopoda: Notostraca) in temporary ponds

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Trans-Generational Influence of Human Disturbances in Japanese Quail: Egg Quality Influences Male Social and Sexual Behaviour

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Silencing the expression of the salivary sheath protein causes transgenerational feeding suppression in the aphid Sitobion avenae

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Isolation ofBacillus schlegelii,a thermophilic,hydrogen oxidizing,aerobic autotroph,from geothermal and nongeothermal environments

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