ABSTRACT
Spermatogenesis, a complex biological process culminating in the generation of mature spermatozoa, involves the mitogen-activated protein kinase (MAPK) cascades in a complex but well-regulated manner. The MAP kinases are the most conserved signal transduction pathways required for a wide range of physiological processes. They play significant roles in the modulation of several male reproductive functions, including germ cell differentiation, apoptosis, sperm maturation, hyperactivation, capacitation and acrosome reaction. In recent years, studies have shown that MAPKs are deeply involved in spermatogenesis through the regulation of junction restructuring, especially the adherens junction (AJ) and ectoplasmic specialization (ES).The testis-specific ectoplasmic specializations (ESs) are basically found at the Sertoli-Sertoli and Sertoli–germ cell interfaces in the seminiferous epithelium and classified as the basal ES (at Sertoli-Sertoli cell interface restricted to BTB coexisting with TJs) and the apical ES (at Sertoli-spermatid interface lacking TJs) with morphological similarity. Herein, we summarize the recent understanding of the role and function of MAP kinases in spermatogenesis with special emphasis on the roles of three major MAPKs; namely, the extracellular signal-regulated kinase (ERK), the c-Jun N-terminal kinase (JNK), and the p38 MAPK, in ES dynamics and germ cell apoptosis. Their potential as novel targets for contraception or infertility management lies in their susceptibility to designed chemical interference through specific activators or inhibitors.
