Exogenous protein kinases A and C, but not endogenous prostasome-associated protein kinase, phosphorylate semenogelins I and II from human semen
2002 (English)In: Journal of Andrology, ISSN 0196-3635, Vol. 23, no 6, 806-814 p.Article in journal (Refereed) Published
Semenogelins I and II are the quantitatively dominating proteinsin humansemen. They comprise the major part of the sperm-entrappinggel formed atejaculation, which subsequently liquefies dueto proteolysis of thegel-forming proteins by prostate-specificantigen (PSA). The mechanism behindgel formation and its physiologicalsignificance is not known. We have studiedphosphorylation anddephosphorylation of human semenogelins. Both werephosphorylatedby protein kinases A and C (PKA and PKC, respectively) at arateabout 5 times less than that of histone. For PKA, incorporated(32P)phosphateinto semenogelin approached a maximum above 1mol/mol. Correspondingvalues for phosphorylation of the semenogelins with PKCweregreater than 10. There was no change in the sensitivity ofphosphosemenogelinsto proteolysis by PSA. Serine (PKA) and serine andthreonine(PKC) were the phosphate-accepting amino acid residues, andallincorporated (32P)phosphate could be removed from the semenogelinswithhuman acid phosphatase. Nil or very little phosphate could bedetected inpurified semenogelins isolated from seminal plasma.In vivo, about half theprotein kinase activity in seminal plasmawas bound to prostasomes. PKA butnot PKC purified from prostasomescould phosphorylate specific substrates, butthey could phosphorylateeither of the semenogelins.
Place, publisher, year, edition, pages
2002. Vol. 23, no 6, 806-814 p.
Acid phosphatase, histone, prostate-specific antigen, vasectomy
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-65798OAI: oai:DiVA.org:uu-65798DiVA: diva2:93709