TY - JOUR
T1 - Shear stress-mediated cytoskeletal remodeling and cortactin translocation in pulmonary endothelial cells
AU - Birukov, Konstantin G.
AU - Birukova, Anna A.
AU - Dudek, Steven M.
AU - Verin, Alexander D.
AU - Crow, Michael T.
AU - Zhan, Xi
AU - DePaola, Natacha
AU - Garcia, Joe G.N.
PY - 2002
Y1 - 2002
N2 - Hemodynamic forces in the form of shear stress (SS) and mechanical strain imposed by circulating blood are recognized factors involved in the control of systemic endothelial cell (EC) cytoskeletal structure and function. However, the effects of acute SS on pulmonary endothelium have not been precisely characterized, nor the mechanism of rapid SS-induced EC cytoskeletal rearrangement understood. We exposed bovine and human pulmonary EC monolayers to laminar SS (10 dynes/ cm2) in a parallel plate flow chamber and observed increased actin stress fiber formation 15 rain after application of flow. Acute SS-induced pronounced cortical cytoskeletal rearrangement characterized by myosin light chain kinase (MLCK)- and Rho-associated kinase (RhoK)-dependent accumulation of diphosphorylated regulatory myosin light chains (MLC) in the cortical actin ring, junctional protein tyrosine phosphorylation, and transient peripheral translocation of cortactin, an actin-binding protein involved in the regulation of actin polymerization. SS-induced cortactin translocation was independent of Erk-1,2 MAP kinase, p60Src, MLCK, or RhoK activities, and unaffected by overexpression of a cortactin mutant lacking four major p60Src phosphorylation sites. However, both SS-induced transient cortactin translocation and cytoskeletal reorientation in response to sustained (24 h) SS was abolished in cells overexpressing either dominant negative Rac 1 or a dominant negative construct of its downstream target, p21-activated kinase (PAK)-1. Our results suggest a potential role for cortactin in the SS-induced EC cortical cytoskeletal remodeling and demonstrate a novel mechanism of Rac GTPase-dependent regulation of the pulmonary endothelial cytoskeleton by SS.
AB - Hemodynamic forces in the form of shear stress (SS) and mechanical strain imposed by circulating blood are recognized factors involved in the control of systemic endothelial cell (EC) cytoskeletal structure and function. However, the effects of acute SS on pulmonary endothelium have not been precisely characterized, nor the mechanism of rapid SS-induced EC cytoskeletal rearrangement understood. We exposed bovine and human pulmonary EC monolayers to laminar SS (10 dynes/ cm2) in a parallel plate flow chamber and observed increased actin stress fiber formation 15 rain after application of flow. Acute SS-induced pronounced cortical cytoskeletal rearrangement characterized by myosin light chain kinase (MLCK)- and Rho-associated kinase (RhoK)-dependent accumulation of diphosphorylated regulatory myosin light chains (MLC) in the cortical actin ring, junctional protein tyrosine phosphorylation, and transient peripheral translocation of cortactin, an actin-binding protein involved in the regulation of actin polymerization. SS-induced cortactin translocation was independent of Erk-1,2 MAP kinase, p60Src, MLCK, or RhoK activities, and unaffected by overexpression of a cortactin mutant lacking four major p60Src phosphorylation sites. However, both SS-induced transient cortactin translocation and cytoskeletal reorientation in response to sustained (24 h) SS was abolished in cells overexpressing either dominant negative Rac 1 or a dominant negative construct of its downstream target, p21-activated kinase (PAK)-1. Our results suggest a potential role for cortactin in the SS-induced EC cortical cytoskeletal remodeling and demonstrate a novel mechanism of Rac GTPase-dependent regulation of the pulmonary endothelial cytoskeleton by SS.
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U2 - 10.1165/ajrcmb.26.4.4725
DO - 10.1165/ajrcmb.26.4.4725
M3 - Article
C2 - 11919082
AN - SCOPUS:0036009459
SN - 1044-1549
VL - 26
SP - 453
EP - 464
JO - American journal of respiratory cell and molecular biology
JF - American journal of respiratory cell and molecular biology
IS - 4
ER -