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Tr‐kit‐induced resumption of the cell cycle in mouse eggs requires activation of a Src‐like kinase
Author(s) -
Sette Claudio,
Paronetto Maria Paola,
Barchi Marco,
Bevilacqua Arturo,
Geremia Raffaele,
Rossi Pellegrino
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf553
Subject(s) - fyn , biology , microbiology and biotechnology , src family kinase , proto oncogene tyrosine protein kinase src , autophosphorylation , microinjection , tyrosine kinase , oocyte activation , proto oncogene proteins c kit , phosphorylation , signal transduction , protein kinase a , oocyte , embryo , stem cell factor , stem cell , haematopoiesis
Microinjection in mouse eggs of tr‐kit, a truncated form of the c‐kit tyrosine kinase present in mouse spermatozoa, causes resumption of meiosis through activation of phospholipase Cγ1 (PLCγ1) and Ca 2+ mobilization from intracellular stores. We show that the Src‐like kinase Fyn phosphorylates Tyr161 in tr‐kit and that this residue is essential for tr‐kit function. Fyn is localized in the cortex region underneath the plasma membrane in mouse oocytes. Using several approaches, we demonstrate that Fyn associates with tr‐kit and that the interaction requires Tyr161. The interaction between tr‐kit and Fyn triggers activation of the kinase as monitored by both autophosphorylation and phosphorylation of PLCγ1. Co‐injection of tr‐kit with the SH2 domain of Fyn, or pre‐treatment with a Fyn inhibitor, impairs oocyte activation, suggesting that activation of Fyn by tr‐kit also occurs in vivo . Finally, microinjection of constitutively active Fyn triggers oocyte activation downstream of tr‐kit but still requires PLC activity. We suggest that the mechanism by which tr‐kit triggers resumption of meiosis of mouse eggs requires a functional interaction with Fyn and phosphorylation of PLCγ1.