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Phosphorylation of Ser 21 in Fyn regulates its kinase activity, focal adhesion targeting, and is required for cell migration
Author(s) -
Yeo Myeong Gu,
Oh Hye Jin,
Cho HongSuk,
Chun Jang Soo,
Marcantonio Eugene E.,
Song Woo Keun
Publication year - 2011
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.22335
Subject(s) - fyn , focal adhesion , ptk2 , microbiology and biotechnology , tyrosine protein kinase csk , tyrosine kinase , phosphorylation , proto oncogene tyrosine protein kinase src , src family kinase , tyrosine phosphorylation , cell adhesion , kinase , biology , signal transduction , sh2 domain , protein kinase a , biochemistry , cell , mitogen activated protein kinase kinase
The tyrosine kinase Fyn is a member of the Src family kinases which are important in many integrin‐mediated cellular processes including cell adhesion and migration. Fyn has multiple phosphorylation sites which can affect its kinase activity. Among these phosphorylation sites, the serine 21 (S21) residue of Fyn is a protein kinase A (PKA) recognition site within an RxxS motif of the amino terminal SH4 domain of Fyn. In addition, S21 is critical for Fyn kinase‐linked cellular signaling. Mutation of S21A blocks PKA phosphorylation of Fyn and alters its tyrosine kinase activity. Expression of Fyn S21A in cells lacking Src family kinases (SYF cell) led to decreased tyrosine phosphorylation of focal adhesion kinase resulting in reduced focal adhesion targeting, which slowed lamellipodia dynamics and thus cell migration. These changes in cell motility were reflected by the fact that cells expressing Fyn S21A were severely deficient in their ability to assemble and disassemble focal adhesions. Taken together, our findings indicate that phosphorylation of S21 within the pPKA recognition site (RxxS motif) of Fyn regulates its tyrosine kinase activity and controls focal adhesion targeting, and that this residue of Fyn is critical for transduction of signals arising from cell‐extracellular matrix interactions. J. Cell. Physiol. 226: 236–247, 2010. © 2010 Wiley‐Liss, Inc.