An X-linked Gene Encodes a Major Human Sperm Fibrous Sheath Protein, hAKAP82
GENOMIC ORGANIZATION, PROTEIN KINASE A-RII BINDING, AND DISTRIBUTION OF THE PRECURSOR IN THE SPERM TAIL*
Abstract
Mammalian sperm motility is regulated by a cascade of cAMP-dependent protein phosphorylation events mediated by protein kinase A. A-kinaseanchor proteins (AKAPs) direct protein kinase A activity by tethering the enzyme near its physiological substrates. We have characterized a major human sperm fibrous sheath AKAP, hAKAP82, and its precursor, pro-hAKAP82, the homologues of the mouse fibrous sheath proteins mAKAP82 and 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 cleavage sites were identical to those of the mouse protein. The genomic organization of mousepro-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-hAKAP82 was processed to hAKAP82 in human sperm. Although pro-mAKAP82 localizes only to the proximal portion of the principal piece of the flagellum, pro-hAKAP82 localized to the entire length of the principal piece. The pro-hAKAP82 gene mapped to human chromosome Xp11.2, indicating that defects in this gene are maternally inherited. These studies suggest several roles for hAKAP82 in sperm motility, including the regulation of signal transduction pathways.
Footnotes
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↵* This work was supported in part by National Institutes of Health Grants HD01189 (to R. M. O. T.) and HD06274 (to S. B. M. and G. L. G.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) AF072756, AF087516, and AF087517.
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↵‡ These authors contributed equally to this work.
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↵§ To whom correspondence should be addressed: Center for Research on Reproduction and Women’s Health, University of Pennsylvania School of Medicine, 3620 Hamilton Walk, John Morgan Bldg., Rm. 305, Philadelphia, PA 19104. Tel.: 215-662-6061; Fax: 215-349-5118; E-mail:smoss{at}mail.med.upenn.edu.
- FS
- fibrous sheath
- PK-A
- protein kinase A
- AKAP
- A-kinase anchor protein
- RII
- regulatory subunit of PK-A
- mAKAP82
- mouse AKAP82
- pro-mAKAP82
- precursor of mAKAP82
- hAKAP82
- human AKAP82
- pro-hAKAP82
- precursor of hAKAP82
- hpro
- pro domain of pro-hAKAP82
- BAC
- bacterial artificial chromosome
- anti-hpro
- antibody against the pro domain of pro-hAKAP82
- EST
- expressed sequence tag
- 5′-UTRf
- sequence representing the 5′-untranslated region of the alternative spliced variant of pro-hAKAP82
- FISH
- fluorescence in situ hybridization
- bp
- base pair(s)
- PCR
- polymerase chain reaction
- PBS
- phosphate-buffered saline.
- Received June 22, 1998.
- Revision received August 7, 1998.
- The American Society for Biochemistry and Molecular Biology, Inc.
