THE FUNCTI0NAL R0LE 0F MEMBRANE-B0UND ADENYLYL CYCLASES AND THE RECEPT0RS AND G-PR0TEINS C0UPLED WITH THEM IN REGULATI0N 0F SPERMAT0Z0A FERTILITY
The cAMP-dependent signaling pathways play a crucial role in regulation of spermatozoa fertility. The cAMP synthesis in spermatozoa is carried out both by soluble and by transmembrane (membrane-bound) forms of adenylyl cyclase (AC). For the last years, numerous data have been appeared on the presence of a wide variety of membrane-bound AC isoforms in spermatozoa at different stages of their maturation and the regulation of the enzymes by hormones and hormone-like substances through G protein-coupled receptors (GPCR). In spermatozoa, functioning as GPCR agonists may be adenosine, biogenic amines, peptide hormones, and odorants. The study of structural-functional organization and regulatory properties of the AC signaling system in spermatozoa is of great practical importance for reproductive technology, as the membrane-bound AC forms and the signaling cascades coupled with them are involved in controlling processes, such as chemotaxis and motility of spermatozoa, their capability for capacitation and acrosomal reaction. In this review the data on the functioning and the role of AC signaling system in spermatozoa of human and vertebrates are summarizes and analyzed, and the achievements and unresolved problems in this area are discussed.