Novel interaction of cortactin with endothelial cell myosin light chain kinase.

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Citation

Dudek SM, Birukov KG, Zhan X, Garcia JG

Novel interaction of cortactin with endothelial cell myosin light chain kinase.

Biochem Biophys Res Commun. 2002 Nov 8;298(4):511-9.

PubMed ID
12408982 [ View in PubMed
]
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 Ca(2+)/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 p60(src) and 80kDa cortactin, an actin-binding protein and known p60(src) 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 (Y(464), Y(471)) or cortactin (Y(421), Y(466), and Y(482)) by p60(src) 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.

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Polypeptides
NameUniProt ID
Myosin light chain kinase, smooth muscleQ15746Details