Regulation of contractility by Hsp27 and Hic-5 in rat mesenteric small arteries.
The regulation of small artery contractility by vasoconstrictors is important for vascular function, and actin cytoskeleton remodeling is required for contraction. p38 MAPK and tyrosine kinases are implicated in actin polymerization and contraction through heat shock protein 27 (Hsp27) and the cytoskeletal protein paxillin, respectively. We evaluated the roles of downstream targets of p38 MAPK and tyrosine kinases in cytoskeletal reorganization and contraction and whether the two signaling pathways regulate contraction independent of each other. We identified the expression of the paxillin homologue hydrogen peroxide-inducible clone-5 (Hic-5) and showed its activation by norepinephrine (NE) in a Src-dependent manner. Furthermore, we demonstrated a NE-induced interaction of proline-rich tyrosine kinase-2 (PYK2) but not Src or p125 focal adhesion kinase with Hic-5. This interaction was Src dependent, suggesting that Hic-5 was a substrate for PYK2 downstream from Src. The activation of Hic-5 induced its relocalization to the cytosol. The parallel activation of Hsp27 by NE was p38 MAPK dependent and led to its dissociation from actin filaments and translocation from membrane to cytosol and increased actin polymerization. Both Hsp27 and Hic-5 activation resulted in their association within the same time frame as NE-induced contraction, and the inhibition of either p38 MAPK or Src inhibited the interaction between Hsp27 and Hic-5 and the contractile response. Furthermore, combined p38 MAPK and Src inhibition had no greater effect on contraction than individual inhibition, suggesting that the two pathways act through a common mechanism. These data show that NE-induced activation and the association of Hsp27 and Hic-5 are required for the reorganization of the actin cytoskeleton and force development in small arteries.
Srinivasan
R
R
Cardiovascular Research Group, University of Manchester, UK.
Forman
S
S
Quinlan
R A
RA
Ohanian
J
J
Ohanian
V
V
D000199:Actins / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047468:Immunoprecipitation; D060588:LIM Domain Proteins; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009363:Neoplasm Proteins / Q000378:metabolism / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D054558:Protein Tyrosine Phosphatases, Non-Receptor / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D019061:src-Family Kinases / Q000037:antagonists & inhibitors
D000199:Actins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486114:Hspb1 protein, rat; D060588:LIM Domain Proteins; D009363:Neoplasm Proteins; D016877:Oxidants; C490352:Tgfb1i1 protein, rat; D014662:Vasoconstrictor Agents; D006861:Hydrogen Peroxide; D019061:src-Family Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D009638:Norepinephrine