Myotubularin phosphoinositide phosphatases, protein phosphatases, and kinases: Their roles in junction dynamics and spermatogenesis
Article first published online: 2 FEB 2005
Copyright © 2005 Wiley-Liss, Inc.
Journal of Cellular Physiology
Volume 204, Issue 2, pages 470–483, August 2005
How to Cite
Zhang, J., Mruk, D. D. and Cheng, C. Y. (2005), Myotubularin phosphoinositide phosphatases, protein phosphatases, and kinases: Their roles in junction dynamics and spermatogenesis. J. Cell. Physiol., 204: 470–483. doi: 10.1002/jcp.20303
- Issue published online: 26 MAY 2005
- Article first published online: 2 FEB 2005
- Manuscript Accepted: 22 NOV 2004
- Manuscript Received: 24 AUG 2004
- The National Institutes of Health. Grant Numbers: U01 HD045908, U54 HD029990
- The CONRAD Program. Grant Numbers: CIG 01-72, CIG 01-74
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.