Structure and Control of a Cell‐Cell Adhesion Complex Associated With Spermiation in Rat Seminiferous Epithelium

Abstract

Spermiation, the release of late spermatids from the Sertoli cell, is disrupted by a number of toxicants. Control of the spermiation process, and the proteins that interact to adhere mature spermatids to Sertoli cells, is poorly understood. In these studies we used immunohistochemistry, coimmunoprecipitation/Western blotting, and mass spectrometry to refine an earlier model of sperm adhesion proposed by our laboratory. We have identified specific proteins linked together as part of a multiprotein complex, as well as several additional proteins (cortactin, ERK1/2, and 14-3-3 zeta) that may be functioning in both structural and signal transduction roles. The current and prior data suggest that protein phosphorylation is central to the control of spermiation. We also present and characterize an in vitro tubule culture system that allowed functional testing of the spermiation model by pharmacologic manipulation, and yielded data consistent with the importance of protein phosphorylation in spermiation.

Blood–testis barrier dynamics are regulated by an engagement/disengagement mechanism between tight and adherens junctions via peripheral adaptors

“…1B i-l). Consistent with earlier reports (25,26), the N-cadherin͞␥-catenin protein complex was also detected outside the basal ES, such as at the apical ES in selected stages of the epithelial cycle (e.g., stages V-VI) (see white arrowheads in Fig. 1B a and i).…”

Anchoring Junctions As Drug Targets: Role in Contraceptive Development

“…Nevertheless, it is interesting to note that there are no reported cases of hemidesmosome disassembly in the testis, suggestive of stable and robust adhesion. Moreover, ␣6␤1 integrin does not seem to localize to the intermediate filament-based hemidesmosome in the testis but apparently to the actin-based basal ectoplasmic specialization (Chapin et al, 2001;Mulholland et al, 2001). In addition, except for a single report published nearly 2 decades ago that described the presence of an uncharacterized 120-kDa protein in the testis referred to as 1-2B7B (Zhang et al, 1991), there has been no advancement in the biology of the hemidesmosome in this organ.…”

“…1). Moreover, both Cdc42 and RhoB have been found to localize at the apical ectoplasmic specialization (Chapin et al, 2001;Lui et al, 2003), illustrating that they are important regulators of Sertoli-spermatid adhesion. Taken collectively, these results demonstrate that adhesion between Sertoli and germ cells in the testis is regulated distinctly from adhesion between Sertoli cells.…”

Metabolic Cooperation in Testis as a Pharmacological Target: From Disease to Contraception

“…The molecular mechanisms involved in the final step of sperm release from SC also remain largely unknown, although various adhesion and signaling molecules have been identified and localized in Sertoli-spermatid junctions [50]. Nevertheless, some studies highlighted that alterations in these adhesion complexes are related with aberrant sperm quality and infertility.…”