scholarly journals Biphasic Regulation of Myosin Light Chain Phosphorylation by p21-activated Kinase Modulates Intestinal Smooth Muscle Contractility

2012 ◽  
Vol 288 (2) ◽  
pp. 1200-1213 ◽  
Author(s):  
Ji Chu ◽  
Ngoc T. Pham ◽  
Nicole Olate ◽  
Karina Kislitsyna ◽  
Mary-Clare Day ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Intestinal Smooth Muscle ◽  
Myosin Light Chain Phosphorylation ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility ◽  
P21 Activated Kinase

scholarly journals Inhibition of Contraction and Myosin Light Chain Phosphorylation in Guinea‐Pig Smooth Muscle by p21‐Activated Kinase 1

2003 ◽  
Vol 549 (2) ◽  
pp. 489-500 ◽  
Author(s):  
A. Wirth ◽  
M. Schroeter ◽  
C. Kock‐Hauser ◽  
E. Manser ◽  
J. M. Chalovich ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Light Chain Phosphorylation ◽  
P21 Activated Kinase

The regulation of smooth muscle contractility by zipper-interacting protein kinaseThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.

2007 ◽  
Vol 85 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Eikichi Ihara ◽  
Justin A. MacDonald
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Specific Inhibitor ◽  
Inhibitory Protein ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility ◽  
Independent Manner ◽  
Interacting Protein

Smooth muscle contractility is mainly regulated by phosphorylation of the 20 kDa myosin light chains (LC20), a process that is controlled by the opposing activities of myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP). Recently, intensive research has revealed that various protein kinase networks including Rho-kinase, integrin-linked kinase, zipper-interacting protein kinase (ZIPK), and protein kinase C (PKC) are involved in the regulation of LC20 phosphorylation and have important roles in modulating smooth muscle contractile responses to Ca2+ (i.e., Ca2+ sensitization and Ca2+ desensitization). Here, we review the general background and structure of ZIPK and summarize our current understanding of its involvement in a number of cell processes including cell death (apoptosis), cell motility, and smooth muscle contraction. ZIPK has been found to induce the diphosphorylation of LC20 at Ser-19 and Thr-18 in a Ca2+-independent manner and to regulate MLCP activity directly through its phosphorylation of the myosin-targeting subunit of MLCP or indirectly through its phosphorylation of the PKC-potentiated inhibitory protein of MLCP. Future investigations of ZIPK function in smooth muscle will undoubtably focus on determining the mechanisms that regulate its cellular activity, including the identification of upstream signaling pathways, the characterization of autoinhibitory domains and regulatory phosphorylation sites, and the development of specific inhibitor compounds.

scholarly journals Arteriolar vasodilation involves actin depolymerization

2018 ◽  
Vol 315 (2) ◽  
pp. H423-H428
Author(s):  
Philip S. Clifford ◽  
Brian S. Ferguson ◽  
Jeffrey L. Jasperse ◽  
Michael A. Hill
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Sodium Nitroprusside ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Muscle Relaxation ◽  
Nitric Oxide Donor ◽  
Smooth Muscle Relaxation ◽  
Myosin Light Chain Phosphorylation ◽  
Actin Depolymerization

It is generally assumed that relaxation of arteriolar vascular smooth muscle occurs through hyperpolarization of the cell membrane, reduction in intracellular Ca2+ concentration, and activation of myosin light chain phosphatase/inactivation of myosin light chain kinase. We hypothesized that vasodilation is related to depolymerization of F-actin. Cremaster muscles were dissected in rats under pentobarbital sodium anesthesia (50 mg/kg). First-order arterioles were dissected, cannulated on glass micropipettes, pressurized, and warmed to 34°C. Internal diameter was monitored with an electronic video caliper. The concentration of G-actin was determined in flash-frozen intact segments of arterioles by ultracentrifugation and Western blot analyses. Arterioles dilated by ~40% of initial diameter in response to pinacidil (1 × 10−6 mM) and sodium nitroprusside (5 × 10−5 mM). The G-actin-to-smooth muscle 22α ratio was 0.67 ± 0.09 in arterioles with myogenic tone and increased significantly to 1.32 ± 0.34 ( P < 0.01) when arterioles were dilated with pinacidil and 1.14 ± 0.18 ( P < 0.01) with sodium nitroprusside, indicating actin depolymerization. Compared with control vessels (49 ± 5%), the percentage of phosphorylated myosin light chain was significantly reduced by pinacidil (24 ± 2%, P < 0.01) but not sodium nitroprusside (42 ± 4%). These findings suggest that actin depolymerization is an important mechanism for vasodilation of resistance arterioles to external agonists. Furthermore, pinacidil produces smooth muscle relaxation via both decreases in myosin light chain phosphorylation and actin depolymerization, whereas sodium nitroprusside produces smooth muscle relaxation primarily via actin depolymerization. NEW & NOTEWORTHY This article adds to the accumulating evidence on the contribution of the actin cytoskeleton to the regulation of vascular smooth muscle tone in resistance arterioles. Actin depolymerization appears to be an important mechanism for vasodilation of resistance arterioles to pharmacological agonists. Dilation to the K+ channel opener pinacidil is produced by decreases in myosin light chain phosphorylation and actin depolymerization, whereas dilation to the nitric oxide donor sodium nitroprusside occurs primarily via actin depolymerization. Listen to this article’s corresponding podcast at https://ajpheart.podbean.com/e/vascular-smooth-muscle-actin-depolymerization/ .

scholarly journals The pathophysiological roles of COX-1 and COX-2 in the intestinal smooth muscle contractility under the anaphylactic condition

2008 ◽  
Vol 29 (2) ◽  
pp. 113-117 ◽  
Author(s):  
Hiroko KADOWAKI ◽  
Takeshi YAMAMOTO ◽  
Natsuko KAGEYAMA-YAHARA ◽  
Nobuo KUROKAWA ◽  
Makoto KADOWAKI
Keyword(s):  
Smooth Muscle ◽  
Intestinal Smooth Muscle ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility ◽  
Cox 2 ◽  
Cox 1

Mechanism of galanin-induced contraction of longitudinal smooth muscle of the rat jejunum

1998 ◽  
Vol 274 (2) ◽  
pp. G306-G313 ◽  
Author(s):  
Simon A. Ahtaridis ◽  
Surender S. Katoch ◽  
Robert S. Moreland
Keyword(s):  
Smooth Muscle ◽  
Pertussis Toxin ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Effective Concentration ◽  
Rat Jejunum ◽  
Myosin Light Chain Phosphorylation ◽  
Half Maximum ◽  
Longitudinal Smooth Muscle ◽  
Intracellular Ca

Intact and α-toxin-permeabilized longitudinal smooth muscle were mounted for measurement of force and myosin light chain phosphorylation. Galanin contracted intact jejunum with a half-maximum effective concentration of 9.2 ± 0.1 nM. Neither atropine, hexamethonium, guanethidine, nor tetrodotoxin affected the contraction. The contraction was also unaffected by depletion of intracellular Ca2+ or by addition of thapsigargin; removal of extracellular Ca2+ or addition of nifedipine abolished the contraction. Galanin increased myosin light chain phosphorylation levels concomitantly with force. During continued tissue stimulation, force fell to suprabasal values, whereas myosin light chain phosphorylation levels remained elevated. Galanin increased Ca2+ sensitivity of contraction in α-toxin-permeabilized tissues, and this was reversed by either guanosine 5′- O-(2-thiodiphosphate) or pertussis toxin. These results suggest that galanin-induced contraction of longitudinal jejunal smooth muscle is dependent on a pertussis toxin-sensitive G protein that is apparently not coupled to the release of intracellular Ca2+but to the influx of extracellular Ca2+ and involves an initial myofilament Ca2+ sensitization followed by Ca2+ desensitization.

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