This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Duncan, A. E. Articles by Fraser, L. R. Search for Related Content PubMed PubMed Citation Articles by Duncan, A. E. Articles by Fraser, L. R.

Cyclic AMP-dependent phosphorylation of epididymal mouse sperm proteins during capacitation in vitro: identification of an M_r 95 000 phosphotyrosine-containing protein

Cyclic AMP-dependent changes in phosphorylation of epididymal mouse sperm suspensions were examined in media designed to manipulate capacitation and the expression of parameters associated with full fertilizing ability, i.e. hyperactivated motility and the acrosome reaction. After initial assessment of cAMP-dependent protein kinase activity in frozen–thawed and lyophilized sperm suspensions using exogenous substrate, phosphorylation of endogenous sperm phosphoproteins was examined using sodium dodecyl sulfate poly-acrylamide gel electrophoresis followed by autoradiography or immunoblotting. Numerous phosphoproteins were detected in both uncapacitated and capacitated suspensions, the majority of which were probably concerned with motility; full expression of fertilizing ability appeared to involve an increase in the amount of endogenous phosphorylation as deduced from the decreased amount of ³²P incorporation in these suspensions. The addition of the cAMP-dependent protein kinase inhibitors, H8 and PKI (6–22) amide, demonstrated that most of the phosphoproteins detected were phosphorylated in a cAMP-dependent manner. Of particular interest was a phosphoprotein with an M_r of about 95 000 which was consistently observed in capacitated suspensions. Evidence suggests that this may be phosphorylated on tyrosine residues, since the inclusion of orthovanadate, a phosphoryltyrosine phosphatase inhibitor, altered phosphorylation of this protein. Furthermore, immunodetection using the antiphosphotyrosine antibody, PY-20, identified five proteins with approximate M_r 116 000, 105 000, 95 000, 86 000, and 76 000, and possibly a sixth at 54 000. The 95 000 protein was consistently diminished in ionophore-treated spermatozoa, indicating that the protein was located in the acrosomal cap region. These results suggest that the protein may be the same phosphotyrosine-containing protein as that described by Leyton and Saling (1989) which has been proposed to play a role in acrosomal exocytosis.

This article has been cited by other articles:

				G. R. Hunnicutt, D. E. Koppel, S. Kwitny, and A. E. Cowan Cyclic 3',5'-AMP Causes ADAM1/ADAM2 to Rapidly Diffuse Within the Plasma Membrane of Guinea Pig Sperm Biol Reprod, November 1, 2008; 79(5): 999 - 1007. [Abstract] [Full Text] [PDF]

				S. Mededovic and L. R Fraser Angiotensin II stimulates cAMP production and protein tyrosine phosphorylation in mouse spermatozoa Reproduction, May 1, 2004; 127(5): 601 - 612. [Abstract] [Full Text] [PDF]

				M. A. Baker, L. Hetherington, H. Ecroyd, S. D. Roman, and R. J. Aitken Analysis of the mechanism by which calcium negatively regulates the tyrosine phosphorylation cascade associated with sperm capacitation J. Cell Sci., January 15, 2004; 117(2): 211 - 222. [Abstract] [Full Text] [PDF]

				N. L. Cross Decrease in Order of Human Sperm Lipids During Capacitation Biol Reprod, August 1, 2003; 69(2): 529 - 534. [Abstract] [Full Text] [PDF]

				M. R. Nimmo and N. L. Cross Structural Features of Sterols Required to Inhibit Human Sperm Capacitation Biol Reprod, April 1, 2003; 68(4): 1308 - 1317. [Abstract] [Full Text] [PDF]

				N. L. Cross Sphingomyelin Modulates Capacitation of Human Sperm In Vitro Biol Reprod, October 1, 2000; 63(4): 1129 - 1134. [Abstract] [Full Text]

				J. T. S. Agustin, C. G. Wilkerson, and G. B. Witman The Unique Catalytic Subunit of Sperm cAMP-dependent Protein Kinase Is the Product of an Alternative Calpha mRNA Expressed Specifically in Spermatogenic Cells Mol. Biol. Cell, September 1, 2000; 11(9): 3031 - 3044. [Abstract] [Full Text]

				R. Ain, K. Uma Devi, S. Shivaji, and P.B. Seshagiri Pentoxifylline-stimulated capacitation and acrosome reaction in hamster spermatozoa: involvement of intracellular signalling molecules Mol. Hum. Reprod., July 1, 1999; 5(7): 618 - 626. [Abstract] [Full Text] [PDF]

				R. K. Naz Involvement of Protein Serine and Threonine Phosphorylation in Human Sperm Capacitation Biol Reprod, June 1, 1999; 60(6): 1402 - 1409. [Abstract] [Full Text]

				M. C. Mahony and T. Gwathmey Protein Tyrosine Phosphorylation during Hyperactivated Motility of Cynomolgus Monkey (Macaca fascicularis) Spermatozoa Biol Reprod, May 1, 1999; 60(5): 1239 - 1243. [Abstract] [Full Text]

				P. Visconti, J. Bailey, G. Moore, D Pan, P Olds-Clarke, and G. Kopf Capacitation of mouse spermatozoa. I. Correlation between the capacitation state and protein tyrosine phosphorylation Development, January 4, 1995; 121(4): 1129 - 1137. [Abstract] [PDF]