Distinct segment-specific functions of calyculin A-sensitive protein phosphatases in the regulation of cAMP-triggered events in ejaculated bull spermatozoa.
Mol Reprod Dev
; 82(3): 232-50, 2015 Mar.
Article
em En
| MEDLINE
| ID: mdl-25735235
ABSTRACT
Livestock spermatozoa possess more tenacious suppressors of cAMP-triggered events-including capacitation-associated changes-than laboratory animal spermatozoa, leading to flagellar hyperactivation. In order to identify the suppressors, we examined effects of an inhibitor of serine/threonine protein phosphatases (calyculin A) on cAMP-triggered changes in the protein phosphorylation state, and subsequent occurrence of hyperactivation and acrosome reaction in ejaculated bull spermatozoa. Ejaculated spermatozoa were incubated in cAMP-supplemented medium, then assessed for motility, acrosome morphology, and phosphorylated protein localization. The addition of calyculin A greatly enhanced cAMP-triggered protein phosphorylation at serine/threonine and tyrosine residues in the connecting piece and induction of flagellar hyperactivation. Most hyperactivated spermatozoa exhibited extremely asymmetrical bends at the middle piece, which produced intensive twisting or figure-eight movements. In the sperm head, however, cAMP-triggered dephosphorylation of serine/threonine-phosphorylated proteins and subsequent acrosome reaction were abolished by the addition of calyculin A. Based on these results, we suggest that calyculin A-sensitive protein phosphatases in the connecting piece are suppressors of cAMP-triggered events leading to hyperactivation. By contrast, similar protein phosphatases in the sperm head accelerate cAMP-triggered events leading to the acrosome reaction. These findings are consistent with the indication that calyculin A-sensitive protein phosphatases have distinct functions in the regulation of cAMP-triggered events in different regions of ejaculated bull spermatozoa.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxazóis
/
Espermatozoides
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AMP Cíclico
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Fosfoproteínas Fosfatases
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Reação Acrossômica
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Flagelos
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article