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Myotubularin phosphoinositide phosphatases, protein phosphatases, and kinases: Their roles in junction dynamics and spermatogenesis
Author(s) -
Zhang Jiayi,
Mruk Dolores D.,
Cheng C. Yan
Publication year - 2005
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.20303
Subject(s) - adherens junction , microbiology and biotechnology , biology , proto oncogene tyrosine protein kinase src , protein tyrosine phosphatase , kinase , cadherin , phosphatase , septate junctions , actin cytoskeleton , phosphorylation , cytoskeleton , cell , biochemistry , intracellular , gap junction
Spermatogenesis in the seminiferous epithelium of the mammalian testis is a dynamic cellular event. It involves extensive restructuring at the Sertoli–germ cell interface, permitting germ cells to traverse the epithelium from basal to adluminal compartment. As such, Sertoli–germ cell actin‐based adherens junctions (AJ), such as ectoplasmic specializations (ES), must disassemble and reassemble to facilitate this event. Recent studies have shown that AJ dynamics are regulated by intricate interactions between AJ integral membrane proteins (e.g., cadherins, α6β1 integrins and nectins), phosphatases, kinases, adaptors, and the underlying cytoskeleton network. For instance, the myotubularin (MTM) phosphoinositide (PI) phosphatases, such as MTM related protein 2 (MTMR2), can form a functional complex with c‐Src (a non‐receptor protein tyrosine kinase). In turn, this phosphatase/kinase complex associates with β‐catenin, a constituent of the N‐cadherin/β‐catenin functional unit at the AJ site. This MTMR2‐c‐Src‐β‐catenin complex apparently regulates the phosphorylation status of β‐catenin, which determines cell adhesive function conferred by the cadherin–catenin protein complex in the seminiferous epithelium. In this review, we discuss the current status of research on selected phosphatases and kinases, and how these proteins potentially interact with adaptors at AJ in the seminiferous epithelium to regulate cell adhesion in the testis. Specific research areas that are open for further investigation are also highlighted. © 2005 Wiley‐Liss, Inc.