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Identification of the proteins present in the bull sperm cytosolic fraction enriched in tyrosine kinase activity: A proteomic approach
Author(s) -
Lalancette Claudia,
Faure Robert L.,
Leclerc Pierre
Publication year - 2006
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200500578
Subject(s) - capacitation , tyrosine phosphorylation , tyrosine , tyrosine kinase , phosphorylation , receptor tyrosine kinase , biology , acrosome reaction , proteomics , microbiology and biotechnology , biochemistry , proto oncogene tyrosine protein kinase src , protein tyrosine phosphatase , protein phosphorylation , signal transduction , protein kinase a , motility , gene , in vitro
Numerous sperm proteins have been identified on the basis of their increase in tyrosine phosphorylation during capacitation. However, the tyrosine kinases present in spermatozoa that are responsible for this phosphorylation remain unknown. As spermatozoa are devoid of transcriptional and translational activities, molecular biology approaches might not reflect the transcriptional pattern in mature spermatozoa. Working directly with the proteins present in ejaculated spermatozoa is the most reliable approach to identify the tyrosine kinases potentially involved in the capacitation‐associated increase in protein tyrosine phosphorylation. A combination of tyrosine kinase assays and proteomic identification tools were used as an approach to identify sperm protein tyrosine kinases. Fractionation by nitrogen cavitation showed that the majority of tyrosine kinase activity is present in the cytosolic fraction of bovine spermatozoa. By the use of Poly‐Glu:Tyr(4:1)‐agarose affinity chromatography, we isolated a fraction enriched in tyrosine kinase activity. Proteomics approaches permitted the identification of tyrosine kinases from three families: Src (Lyn), Csk, and Tec (Bmx, Btk). We also identified proteins implicated in different cellular events associated with sperm capacitation and acrosome reaction. These results confirm the implication of tyrosine phosphorylation in some aspects of capacitation/acrosome reaction and reveal the identity of new players potentially involved in these processes.