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Selective interaction of CaMKIIδ 2 and Fyn mediates vascular smooth muscle (VSM) cell motility
Author(s) -
Ginnan Roman,
Zou Xiaojing,
Singer Harold
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.948.8
Subject(s) - fyn , paxillin , microbiology and biotechnology , focal adhesion , motility , chemistry , phosphorylation , biology , proto oncogene tyrosine protein kinase src
Our previous study demonstrated that CaMKIIδ 2 and Fyn physically interact via CaMKIIδ 2 's C ‐terminal “tail”. We also reported that this interaction between CaMKIIδ 2 and Fyn positively mediates VSM cell motility. The purpose of this study is to better understand the mechanistic relationship between CaMKIIδ 2 and Fyn and to clarify their cooperative role in migrating VSM cells. With immunofluorescence, we show that SiRNA depletion of CaMKIIδ in VSM cells attenuated PDGF‐dependent translocation of Fyn to peripheral membranes. Similarly, overexpression of CaMKIIδ 6 , which does not interact with Fyn, also reduced Fyn's ability to translocate to the plasma membrane in response to PDGF. Furthermore, overexpression of CaMKIIδ 6 reduced VSM cell motility in both a scratch wound assay and a transwell assay. The rate of focal adhesion protein recruitment to focal adhesions is directly linked to cell motility. Using TIRF/FRAP in cells overexpressing GFP‐tagged Paxillin, we show that SiRNA mediated loss of CaMKIIδ 2 or Fyn disrupted the kinetics of focal adhesion turnover. Stimulation of VSM cells with PDGF results in tyrosine phosphorylation of P130Cas and Paxillin, both known substrates of Fyn. Along with preventing Fyn translocation to the plasma membrane, overexpression of CaMKIIδ 6 inhibited this PDGF‐dependent phosphorylation of P130Cas and Paxillin. Therefore, we conclude that CaMKIIδ2 “delivers” Fyn to peripheral membranes proximal to focal adhesions where Fyn modulates focal adhesion dynamics and subsequent VSM cell motility.