Novel interaction of cortactin with endothelial cell myosin light chain kinase

Steven M. Dudek, Konstantin G. Birukov, Xi Zhan, Joe G.N. Garcia

Research output: Contribution to journalArticle

75 Scopus citations

Abstract

Inflammatory mediators such as thrombin evoke increases in vascular permeability through activation of endothelial contractile mechanisms which involve increased levels of MLC phosphorylation catalyzed by Ca2+/calmodulin-dependent myosin light chain kinase (MLCK). We previously noted that the high molecular weight endothelial MLCK isoform (EC MLCK) is stably associated with a complex containing p60src and 80 kDa cortactin, an actin-binding protein and known p60src target. In this study we have utilized in vitro binding assays to confirm specific interaction between EC MLCK and cortactin. Tyrosine phosphorylation of either EC MLCK (Y464, Y471) or cortactin (Y421, Y466, and Y482) by p60src significantly increased this direct association. Site-specific antibody and peptide studies subsequently confirmed EC MLCK AA #972-979 and 1019-1025 as sites of cortactin interaction. EC MLCK-cortactin interaction in vitro failed to modulate MLCK enzymatic activity but appeared to inhibit EC MLCK binding to F-actin, while EC MLCK abolished cortactin-mediated augmentation of Arp2/3-stimulated actin polymerization. These data suggest that cortactin-EC MLCK interaction may be a novel determinant of endothelial cortical actin-based cytoskeletal rearrangement.

Original languageEnglish (US)
Pages (from-to)511-519
Number of pages9
JournalBiochemical and Biophysical Research Communications
Volume298
Issue number4
DOIs
StatePublished - Jan 1 2002
Externally publishedYes

Keywords

  • Arp 2/3 complex
  • Cortactin
  • Cytoskeleton
  • Endothelial cell MLCK
  • p60

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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