Structure and control of a cell-cell adhesion complex associated with spermiation in rat seminiferous epithelium

Spermiation, the release of late spermatids from the Sertoli cell, is disru pted by a number of toxicants. Control of the spermiation process, and the proteins that interact to adhere mature spermatids to Sertoli cells, is poo rly understood. In these studies we used immunohistochemistry, coimmunoprec ipitation/Western blotting, and mass spectrometry to refine an earlier mode l of sperm adhesion proposed by our laboratory. We have identified specific proteins linked together as part of a multiprotein complex, as well as sev eral additional proteins (cortactin, ERK1/2, and 14-3-3 zeta) that may be f unctioning in both structural and signal transduction roles. The current an d prior data suggest that protein phosphorylation is central to the control of spermiation. We also present and characterize an in vitro tubule cultur e system that allowed functional testing of the spermiation model by pharma cologic manipulation, and yielded data consistent with the importance of pr otein phosphorylation in spermiation.