Heat shock protein 20-mediated force suppression in forskolin-relaxed swine carotid artery

Meeks, Melissa K.; Ripley, Marcia L.; Jin, Zhicheng; Rembold, Christopher M.

doi:10.1152/ajpcell.00269.2004

Cited by 43 publications

(52 citation statements)

References 25 publications

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“…The dynamic feature of the actin cytoskeleton has also been observed in other studies; the amount of actin monomers is decreased, or the fraction of filamentous actin is increased during contractile stimulation [8][9][10][11][12][13][14][15][16] . In cultured airway smooth muscle cells, treatment with carbachol and endothelin-1 leads to the increase in the ratio of F-actin to G-actin as estimated by cytofluorescence analysis, whereas treatment with smooth muscle relaxant (isoproteronol and forskolin) decreases the F-actin/G-actin ratio 17, 18 .…”

Section: Physiologic Properties Of the Actin Cytoskeleton In Arterialsupporting

confidence: 71%

Physiologic Properties and Regulation of the Actin Cytoskeleton in Vascular Smooth Muscle

Tang

Anfinogenova

2008

J Cardiovasc Pharmacol Ther

150

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Vascular smooth muscle tone plays a fundamental role in regulating blood pressure, blood flow, microcirculation, and other cardiovascular functions. The cellular and molecular mechanisms by which vascular smooth muscle contractility is regulated are not completely elucidated. Recent studies show that the actin cytoskeleton in smooth muscle is dynamic, which regulates force development. In this review, evidence for actin polymerization in smooth muscle upon external stimulation is summarized. Protein kinases, such as Abl, FAK, Src, and MAP kinase, have been documented to coordinate actin polymerization in smooth muscle. Transmembrane integrins have also been reported to link to signaling pathways modulating actin dynamics. The roles of Rho family of the small GTPases and the actin-regulatory proteins including CAS, N-WASP, the Arp2/3 complex, profilin, and heat shock proteins in regulating actin assembly are discussed. These new findings promote our understanding on how smooth muscle contraction is regulated at cellular and molecular levels.

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Section: Physiologic Properties Of the Actin Cytoskeleton In Arterialsupporting

confidence: 71%

Physiologic Properties and Regulation of the Actin Cytoskeleton in Vascular Smooth Muscle

Tang

Anfinogenova

2008

J Cardiovasc Pharmacol Ther

150

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“…Ratios of F/G-actin in these tissues were evaluated using a fractionation assay. 1,3,8,9,29 Stimulation with PE led to the increase in F/G-actin ratios in untreated arteries and segments producing luciferase shRNA. However, the increase in F/G-actin ratios on PE stimulation was dramatically depressed in Abl-deficient resistance arteries.…”

Section: Increases In F/g-actin Ratios Elicited By Pe Are Attenuated mentioning

confidence: 98%

“…[1][2][3]8,9,29 Abl has been implicated in regulating the actin cytoskeleton in nonmuscle cells such as fibroblasts and COS cells. 19,20 We evaluated the effects of Abl downregulation on F/G-actin ratios in resistance arteries on contractile stimulation.…”

Section: Increases In F/g-actin Ratios Elicited By Pe Are Attenuated mentioning

confidence: 99%

Abl Silencing Inhibits CAS-Mediated Process and Constriction in Resistance Arteries

Anfinogenova

Wang

et al. 2007

Circulation Research

144

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Abstract-The tyrosine phosphorylated protein Crk-associated substrate (CAS) has previously been shown to participate in the cellular processes regulating dynamic changes in the actin architecture and arterial constriction. In the present study, treatment of rat mesenteric arteries with phenylephrine (PE) led to the increase in CAS tyrosine phosphorylation and the association of CAS with the adapter protein CrkII. CAS phosphorylation was catalyzed by Abl in an in vitro study. To determine the role of Abl tyrosine kinase in arterial vessels, plasmids encoding Abl short hairpin RNA (shRNA) were transduced into mesenteric arteries by chemical loading plus liposomes. Abl silencing diminished increases in CAS phosphorylation on PE stimulation. Previous studies have shown that assembly of the multiprotein compound containing CrkII, neuronal Wiskott-Aldrich Syndrome Protein (N-WASP) and the Arp2/3 (Actin Related Protein) complex triggers actin polymerization in smooth muscle as well as in nonmuscle cells. In this study, Abl silencing attenuated the assembly of the multiprotein compound in resistance arteries on contractile stimulation. Furthermore, the increase in F/G-actin ratios (an index of actin assembly) and constriction on contractile stimulation were reduced in Abl-deficient arterial segments compared with control arteries. However, myosin regulatory light chain phosphorylation (MRLCP) elicited by contractile activation was not inhibited in Abl-deficient arteries. These results suggest that Abl may play a pivotal role in mediating CAS phosphorylation, the assembly of the multiprotein complex, actin assembly, and constriction in resistance arteries. Abl does not participate in the regulation of myosin activation in arterial vessels during contractile stimulation. Key Words: tyrosine kinase Ⅲ actin cytoskeleton Ⅲ contraction Ⅲ vascular smooth muscle Ⅲ adapter protein A ctin cytoskeleton remodeling has recently emerged as an important cellular process mediating smooth muscle contraction. 1-7 A pool of globular actin (G-actin) is stimulated onto filamentous actin (F-actin) in a variety of smooth muscle cells and tissues in response to agonist stimulation. Blockage of actin polymerization by the inhibitors cytochalasin and latrunculin attenuates active force on activation with contractile stimuli whereas myosin regulatory light chain phosphorylation (MRLCP) is not disrupted. 5,8 -10 These studies suggest that actin dynamics and MRLCP are independently regulated, and that both dynamic changes in the actin cytoskeleton and myosin activation are required for force development during contractile stimulation of smooth muscle. 4,8 -11 However, the mechanisms that regulate the actin cytoskeleton in smooth muscle are not completely understood.The tyrosine phosphorylated protein Crk-associated substrate (CAS) has been implicated in the modulation of the actin cytoskeleton in smooth muscle cells as well as in nonmuscle cells including COS-7 cells and NIH3T3 cells. 9,12-14 Downregulation of CAS by antisense dramatically attenu...

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“…The relative amount of filamentous actin (F-actin) versus total actin was determined with a commercial kit (BK037) from Cytoskeleton (Denver, CO) as previously described (12,25). The amount of force augmentation was not determined in these tissues, so mean force augmentation in similarly treated tissues (from the paxillin measurements) was compared with mean F-actin data in Fig.…”

Section: Methodsmentioning

confidence: 99%

Force augmentation and stimulated actin polymerization in swine carotid artery

Tejani

Rembold

2010

American Journal of Physiology-Cell Physiology

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Tejani AD, Rembold CM. Force augmentation and stimulated actin polymerization in swine carotid artery. Am J Physiol Cell Physiol 298: C182-C190, 2010. First published October 14, 2009 doi:10.1152/ajpcell.00326.2009.-The phenomenon of posttetanic potentiation, in which a single submaximal contraction or series of submaximal contractions strengthens a subsequent contraction, has been observed in both skeletal and cardiac muscle. In this study, we describe a similar phenomenon in swine carotid arterial smooth muscle. We find that a submaximal K ϩ depolarization increases the force generation of a subsequent maximal K ϩ depolarization; we term this "force augmentation." Force augmentation was not associated with a significant increase in crossbridge phosphorylation or shortening velocity during the maximal K ϩ depolarization, suggesting that the augmented force was not caused by higher crossbridge phosphorylation or crossbridge cycling rates. We found that the characteristics of the tissue before the maximal K ϩ depolarization predicted the degree of force augmentation. Specifically, measures of stimulated actin polymerization (higher prior Y118 paxillin phosphorylation, higher prior F-actin, and transition to a more solid rheology evidenced by lower noise temperature, hysteresivity, and phase angle) predicted the subsequent force augmentation. Increased prior contraction alone did not induce force augmentation since readdition of Ca 2ϩ to Ca 2ϩ -depleted tissues induced a partial contraction that was not associated with changes in noise temperature or with subsequent force augmentation. These data suggest that stimulated actin polymerization may produce a substrate for increased crossbridge mediated force, a process we observe as force augmentation. phase angle; noise temperature; paxillin; rheology; vascular smooth muscle IN SKELETAL AND CARDIAC MUSCLE, a single submaximal contraction resulting from a single action potential is referred to as a twitch, and the sustained contraction resulting from repetitive action potentials is referred to as tetanus. In both skeletal and cardiac muscle, both twitches and submaximal tetany will potentiate a subsequent contraction induced by maximal tetany, a phenomenon termed posttetanic potentiation. Skeletal muscle posttetanic potentiation is thought to be caused by crossbridge phosphorylation (31). In this study, we describe a similar phenomenon in arterial smooth muscle in which a submaximal K ϩ contraction increases the maximum force of a subsequent maximal K ϩ contraction, a phenomenon we term "force augmentation." We find, however, that force augmentation in smooth muscle is associated with stimulated actin polymerization and not by increased crossbridge phosphorylation or shortening velocity.It is widely accepted that most forms of arterial smooth muscle contraction primarily involve increased myoplasmic calcium ([Ca 2ϩ ] i ), which increases crossbridge phosphorylation on Ser 19 of the myosin regulatory light chain (MRLC) via MRLC kinase (reviewed in Ref. 15). Contr...

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Heat shock protein 20-mediated force suppression in forskolin-relaxed swine carotid artery

Cited by 43 publications

References 25 publications

Physiologic Properties and Regulation of the Actin Cytoskeleton in Vascular Smooth Muscle

Physiologic Properties and Regulation of the Actin Cytoskeleton in Vascular Smooth Muscle

Abl Silencing Inhibits CAS-Mediated Process and Constriction in Resistance Arteries

Force augmentation and stimulated actin polymerization in swine carotid artery

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