A Kinase Anchor Protein 4 (AKAP4)

AKAP4 encodes a member of the AKAP family. Mammalian sperm motility is regulated by a cascade of cAMP-dependent protein phosphorylation events mediated by protein kinase A. The encoded protein is localized to the sperm flagellum and may be involved in the regulation of sperm motility. Alternative splicing of this gene results in two transcript variants encoding different isoforms.The 860-amino acid polypeptide contains a secretory signal sequence, 5 glycosylation sites, 7 myristoylation sites, and numerous phosphorylation sites. The HI protein, encoded by the AKAP82 gene, has structural homology to other members of the AKAP family. In situ hybridization studies of human testis sections revealed that the HI protein is transcribed postmeiotically in round spermatids.