Rmo. Turner et al., AN X-LINKED GENE ENCODES A MAJOR HUMAN SPERM FIBROUS SHEATH PROTEIN, HAKAP82, The Journal of biological chemistry, 273(48), 1998, pp. 32135-32141
Mammalian sperm motility is regulated by a cascade of cAMP-dependent p
rotein phosphorylation events mediated by protein kinase A. A-kinase a
nchor proteins (AKAPs) direct protein kinase A activity by tethering t
he enzyme near its physiological substrates, We have characterized a m
ajor human sperm fibrous sheath AKAP, hAKAP82, and its precursor, pro-
hAKAP82, the homologues of the mouse fibrous sheath proteins mAKAP82 a
nd pro-mAKAP82. The cDNA sequence of pro-hAKAP82 was highly homologous
to the mouse sequence, and the functional domains of the pro-hAKAP82
protein, the protein kinase A binding, and the pro-hAKAP82/hAKAP82 cle
avage sites were identical to those of the mouse protein. The genomic
organization of mouse pro-AKAP82 was determined. Alternative splicing
occurred in both the mouse and human pro-AKAP82 genes that resulted in
at least two distinct transcripts and possibly two different proteins
. Compared with pro-mAKAP82, considerably less pro-hAKAP8a was process
ed to hAKAP82 in human sperm. Although pro-mAKAP82 localizes only to t
he proximal portion of the principal piece of the flagellum, pro-hAKAP
82 localized to the entire length of the principal piece. The pro-hAKA
P82 gene mapped to human chromosome Xp11.2, indicating that defects in
this gene are maternally inherited, These studies suggest several rol
es for hAKAP82 in sperm motility, including the regulation of signal t
ransduction pathways.