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Changes in tyrosine phosphorylation associated with true capacitation and capacitation‐like state in boar spermatozoa
Author(s) -
Bravo M.M.,
Aparicio I.M.,
GarciaHerreros M.,
Gil M.C.,
Peña F.J.,
GarciaMarin L.J.
Publication year - 2005
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20286
Subject(s) - capacitation , boar , tyrosine phosphorylation , biology , phosphorylation , sperm , tyrosine , andrology , incubation , acrosome , microbiology and biotechnology , biochemistry , medicine , botany
Capacitation is defined as a series of events that render boar sperm competent to fertilize, either in vivo or in vitro. Moreover, preliminary stages of cryopreservation of spermatozoa involving cooling to 5°C have been shown to induce capacitation‐like changes in boar spermatozoa. Capacitation of boar spermatozoa is accompanied by protein phosphorylation, however the relationship between both processes is poorly understood. Capacitation status was assessed by chlortetracycline (CTC) staining. Changes in protein tyrosine phosphorylation were examined in pre‐cleared whole cell lysates using a specific anti‐phosphotyrosine monoclonal antibody. Our results in boar spermatozoa show a significant positive correlation between p32 tyrosine phosphorylation levels and percentage of capacitated (CTC pattern B) spermatozoa. Moreover, incubation of boar spermatozoa with two unrelated tyrosine kinase inhibitors induces a significant reduction in the percentages of capacitated and acrosome‐reacted (AR) boar spermatozoa and a reduction in the p32 tyrosine phosphorylation. In our conditions, cooling boar spermatozoa to 5°C and rewarming to 39°C in a noncapacitating medium results in similar CTC staining patterns to those obtained after incubation of boar sperm for 1 or 4 hr at 39°C in a capacitating medium. However, cooled‐rewarmed fails to induce an increase in p32 tyrosine phosphorylation in boar spermatozoa. Moreover, CTC staining patterns of cooled‐rewarmed spermatozoa do not change after incubation with a tyrosine kinase inhibitor. In conclusion, our results show a direct relationship between capacitation and tyrosine phosphorylation and suggest that p32 tyrosine phosphorylation levels could be used as a marker of the true capacitation changes observed in boar spermatozoa. Moreover, our results show that true capacitation and capacitation‐like changes induced after cooling involve alternative intracellular tyrosine phosphorylation pathways in boar spermatozoa. Mol. Reprod. Dev. 71: 88–96, 2005. © 2005 Wiley‐Liss, Inc.