Sertoli-Germ Cell Adherens Junction Dynamics in the Testis Are Regulated by RhoB GTPase via the ROCK/LIMK Signaling Pathway

摘要: During spermatogenesis, cell-cell actin-based adherens junctions (AJs), such as ectoplasmic specializations (ESs), between Sertoli and germ cells undergo extensive restructuring in the seminiferous epithelium to facilitate cell movement across epithelium. Although mechanism(s) that regulates AJ dynamics testis is virtually unknown, Rho GTPases have been implicated regulation of these events other epithelia. Studies shown vitro assembly Sertoli-germ AJs but not tight (TJs) associated with a transient significant induction RhoB. Immunohistochemistry has localization RhoB stage specific, being lowest stages VII-VIII prior spermiation, displays cell-specific association during epithelial cycle. Throughout cycle, was localized near site basal apical ESs restricted periphery nuclei elongating (but elongated) spermatids, spermatocytes, cells. However, detected at VII-VIII. Furthermore, disruption cocultures either by hypotonic treatment or 1-(2,4-dichlorobenzyl)-indazole-3-carbohydrazide (AF-2364) also induced expression. When adult rats were treated AF-2364 perturb vivo, approximately 4-fold testis, kidney brain, within 1 h, least 1-4 days before loss from could be histological analysis. The signaling pathway(s) which perturbed apparently began an initial activation integrin, turn activated RhoB, ROCK1, (Rho-associated protein kinase 1, called ROKbeta), LIMK1 (LIM lin-11 isl-1 mec3 1), cofilin p140mDia profilin via phosphorylation. Immunoprecipitation immunoblots revealed mediated increase its phospho-Ser phospho-Tyr content. Y-27632 ([(R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexane-carboxamide, 2HCl]), specific ROCK inhibitor, effectively delay AF-2364-induced illustrating integrin/RhoB/ROCK/LIMK pathway indeed plays crucial role dynamics. fact brain suggests exerts effects primarily testis-specific ES multiprotein complex structures spermatids. In summary, this report illustrates are regulated, part, integrin/ROCK/LIMK/cofilin pathway.