title: Rho-ROCK-LIMK-cofilin pathway regulates shear stress activation of sterol regulatory element binding proteins.
abstract: Previous studies have shown that integrin activation and fluid shear stress can modulate the activity of sterol regulatory element binding proteins (SREBPs) in vascular endothelial cells. We investigated the role of small GTPase Rho-mediated signal transduction pathway in this mode of SREBP activation. Fluid shear stress activates the Rho downstream effectors ROCK, LIM kinase (LIMK), and cofilin. The various negative mutants of RhoA, ROCK, LIMK, and cofilin can block the shear stress activation of SREBPs. The shear stress-activated SREBP depends on S2P proteases but not caspase-3. Mechanistically, the endoplasmic reticulum-to-Golgi transport of SREBP cleavage-activating protein requires the actin-based cytoskeleton and is enhanced by the Rho-ROCK-LIMK-cofilin pathway. By enhancing the SREBP-mediated cholesterol metabolism, this unique mechanism may contribute to endothelial cell functions under flow.
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside, Riverside, Calif 92521-0121, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Lin
authors.forename: Lingfang
authors.initials: L
authors.lastname: Zeng
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Kathryn
authors.initials: K
authors.lastname: DeFea
authors.forename: Martin A
authors.initials: MA
authors.lastname: Schwartz
authors.forename: Shu
authors.initials: S
authors.lastname: Chien
authors.forename: John Y-J
authors.initials: JY
authors.lastname: Shyy
mesh_terms: D051339:Actin Depolymerizing Factors; D000199:Actins / Q000378:metabolism; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D002417:Cattle; D002448:Cell Adhesion; D002478:Cells, Cultured; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D054461:Lim Kinases; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D013314:Stress, Mechanical; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D054460:rho-Associated Kinases
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D011506:Proteins; C497387:SREBF1 protein, human; C497390:SREBF2 protein, human; C102196:SREBP cleavage-activating protein; D051780:Sterol Regulatory Element Binding Protein 1; D051782:Sterol Regulatory Element Binding Protein 2; D014157:Transcription Factors; D008156:Luciferases; D011494:Protein Kinases; C515892:LIMK1 protein, human; D054461:Lim Kinases; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020741:rho GTP-Binding Proteins