Protein kinase A-anchoring inhibitor peptides arrest mammalian sperm motility

Srinivasan Vijayaraghavan, Said A. Goueli, Michael P. Davey, Daniel W. Carr

Research output: Contribution to journalArticlepeer-review

211 Scopus citations


Cyclic AMP-dependent protein kinase (PKA) is anchored at specific subcellular sites through the interaction of the regulatory subunit (R) with protein kinase A-anchoring proteins (AKAPs) via an amphipathic helix binding motif. Synthetic peptides containing this amphipathic helix domain competitively disrupt PKA binding to AKAPs and cause a loss of PKA modulation of cellular responses. In this report we use S-Ht31, a cell-permeant anchoring inhibitor peptide, to study the role of PKA anchoring in sperm. Our analysis of three species of mammalian sperm detected three isoforms of PKA (RIIα, RIIβ, and RIβ) and one 110-kDa AKAP. The addition of S-Ht31 to bovine caudal epididymal sperm inhibits motility in a time- and concentration-dependent manner. A control peptide, S-Ht31-P, identical to S- Ht31 except for a proline for isoleucine substitution to prevent amphipathic helix formation, had no effect on motility. The inhibition of motility by S- Ht31 is reversible but only if calcium is present in the suspension buffer, suggesting a role for PKA anchoring in regulating cellular calcium homeostasis. Surprisingly, inhibition of PKA catalytic activity had little effect on basal motility or motility stimulated by agents previously thought to work via PKA activation. These data suggest that the interaction of the regulatory subunit of PKA with sperm AKAPs, independent of PKA catalytic activity, is a key regulator of sperm motility and that disruption of this interaction using cell-permeable anchoring inhibitor peptides may form the basis of a sperm-targeted contraceptive.

Original languageEnglish (US)
Pages (from-to)4747-4752
Number of pages6
JournalJournal of Biological Chemistry
Issue number8
StatePublished - Feb 21 1997

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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