title: Regulation of hyperactivation by PPP2 in hamster spermatozoa.
abstract: It has been widely accepted that serine/threonine protein phosphatases (PPPs) are associated with the regulation of sperm hyperactivation. In the present study, we examined the types of PPPs associated with the regulation of hamster sperm hyperactivation. Protein phosphatases PPP1CA, PPP1CC, PPP2, and PPP3 are present in hamster sperm. In the experiments using several inhibitors, sperm hyperactivation was enhanced when PPP2 was inhibited at least, although inhibition of PPP1 also enhanced sperm hyperactivation. Interestingly, sperm were hyperactivated after PPP2 became an inactive form. And then, PPP1CA became an active form after sperm were hyperactivated. It has also been widely accepted that tyrosine phosphorylation is closely associated with the regulation of sperm hyperactivation. When PPP2 was inhibited, tyrosine phosphorylation was not enhanced at all. On the other hand, inhibition of PPP1 enhanced tyrosine phosphorylation. From the results, it is likely that PPP2 is closely associated with the regulation of sperm hyperactivation, although it is not associated with the regulation of tyrosine phosphorylation.
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi 329-0498, Japan. statsuya@jichi.ac.jp
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Suzuki
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Fujinoki
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shibahara
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005407:Flagella / Q000187:drug effects / Q000502:physiology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000502:physiology; D008297:Male; D008647:Mesocricetus; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000502:physiology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D013075:Sperm Capacitation / Q000502:physiology; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D007527:Isoenzymes; D019000:Phosphotyrosine; D014443:Tyrosine; D054648:Protein Phosphatase 2