scholarly journals The non-kinase activity of myosin light chain kinase in regulating smooth muscle contraction

2009 ◽  
Vol 133 (3) ◽  
pp. 144-148
Author(s):  
Akio Nakamura
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Kinase Activity ◽  
Smooth Muscle Contraction

Calcium-dependent mechanisms of regulation of smooth muscle contraction

1991 ◽  
Vol 69 (12) ◽  
pp. 771-800 ◽  
Author(s):  
Michael P. Walsh
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Binding Protein ◽  
Smooth Muscle Contraction ◽  
Light Chains ◽  
Contractile State ◽  
Calmodulin Binding

The contractile state of smooth muscle is regulated primarily by the sarcoplasmic (cytosolic) free Ca2+ concentration. A variety of stimuli that induce smooth muscle contraction (e.g., membrane depolarization, α-adrenergic and muscarinic agonists) trigger an increase in sarcoplasmic free [Ca2+] from resting levels of 120–270 to 500–700 nM. At the elevated [Ca2+], Ca2+ binds to calmodulin, the ubiquitous and multifunctional Ca2+-binding protein. The interaction of Ca2+ with CaM induces a conformational change in the Ca2+-binding protein with exposure of a site(s) of interaction with target proteins, the most important of which in the context of smooth muscle contraction is the enzyme myosin light chain kinase. The interaction of calmodulin with myosin light chain kinase results in activation of the kinase that catalyzes phosphorylation of myosin at serine-19 of each of the two 20-kDa light chains (native myosin is a hexamer composed of two heavy chains (230 kDa each) and two pairs of light chains (one pair of 20 kDa each and the other pair of 17 kDa each)). This simple phosphorylation reaction triggers cycling of myosin cross-bridges along actin filaments and the development of force. Relaxation of the muscle follows removal of Ca2+ from the sarcoplasm, whereupon calmodulin dissociates from myosin light chain kinase regenerating the inactive kinase; myosin is dephosphorylated by myosin light chain phosphatase(s), whereupon it dissociates and remains detached from the actin filament and the muscle relaxes. A substantial body of evidence has been accumulated in support of this central role of myosin phosphorylation–dephosphorylation in the regulation of smooth muscle contraction. However, a wide range of physiological and biochemical studies supports the existence of additional, secondary Ca2+-dependent mechanisms that can modulate or fine-tune the contractile state of the smooth muscle cell. Three such mechanisms have emerged: (i) the actin-, tropomyosin-, and calmodulin-binding protein, calponin; (ii) the actin-, myosin-, tropomyosin-, and calmodulin-binding protein, caldesmon; and (iii) the Ca2+- and phospholipid-dependent protein kinase (protein kinase C).Key words: smooth muscle, Ca2+, myosin phosphorylation, regulation of contraction.

scholarly journals Fractional activation of myosin light chain kinase is sufficient for robust smooth muscle contraction

2011 ◽  
Vol 25 (S1) ◽  
Author(s):  
Ning Gao ◽  
Jian Huang ◽  
Wei‐Qi He ◽  
Min‐sheng Zhu ◽  
Kristine E. Kamm ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Smooth Muscle Contraction

scholarly journals Myosin Light Chain Kinase Is Central to Smooth Muscle Contraction and Required for Gastrointestinal Motility in Mice

2008 ◽  
Vol 135 (2) ◽  
pp. 610-620.e2 ◽  
Author(s):  
Wei–Qi He ◽  
Ya–Jing Peng ◽  
Wen–Cheng Zhang ◽  
Ning Lv ◽  
Jing Tang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Gastrointestinal Motility ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Smooth Muscle Contraction

scholarly journals Myosin Light Chain Kinase Is Necessary for Tonic Airway Smooth Muscle Contraction

2009 ◽  
Vol 285 (8) ◽  
pp. 5522-5531 ◽  
Author(s):  
Wen-Cheng Zhang ◽  
Ya-Jing Peng ◽  
Gen-Sheng Zhang ◽  
Wei-Qi He ◽  
Yan-Ning Qiao ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Airway Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Smooth Muscle Contraction

Smooth Muscle Contraction: Recent Advances

1994 ◽  
Vol 72 (11) ◽  
pp. 1317-1319
Author(s):  
Newman L. Stephens
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Myosin Light Chain ◽  
Kinase Activity ◽  
Smooth Muscle Contraction ◽  
Recent Advances ◽  
Regulation Of Contraction ◽  
Muscle Biochemistry ◽  
Remarkable Progress ◽  
Made In

Research in smooth muscle contraction has shown remarkable progress over the last 5 years. Striking advances have been made in the areas of biochemical regulation of contraction, centering on myosin light chain kinase activity, and of biophysical delineation of the contractile process at the actomyosin level by use of the newly developed motility assay. The purpose of the symposium held at Minaki, Ont., was to obtain a comprehensive reporting of the recent advances made in the area of smooth muscle contraction. Specifically, advances in the areas of biophysics of contraction, energetics, and contractile and regulator proteins (including the interesting newcomers caldesmon and calponin) and the changes that occur in pathophysiological entities such as asthma, hypertension, anaphylactic shock, high-altitude hypoxia, and persistent pulmonary hypertension of the newborn were presented.Key words: smooth muscle biophysics, smooth muscle biochemistry, energetics of smooth muscle, pathophysiology of smooth muscle.

Regulation of Myosin Light Chain Kinase Activity in Smooth Muscle

1995 ◽  
pp. 139-158 ◽  
Author(s):  
Kristine E. Kamm ◽  
Katherine Luby-Phelps ◽  
Malu G. Tansey ◽  
Patricia J. Gallagher ◽  
James T. Stull
Keyword(s):  
Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Kinase Activity

Regulation of vascular smooth muscle contraction: myosin light chain phosphorylation dependent and independent pathways

1994 ◽  
Vol 72 (11) ◽  
pp. 1386-1391 ◽  
Author(s):  
Yawen Zhang ◽  
Suzanne Moreland ◽  
Robert S. Moreland
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Smooth Muscle Contraction ◽  
Mitogen Activated Protein ◽  
Vascular Smooth Muscle Contraction ◽  
Triton X ◽  
Mlc Phosphorylation

Ca2+-dependent myosin light chain (MLC) phosphorylation is an important step in the initiation of smooth muscle contraction. However, MLC phosphorylation alone cannot account for all aspects of contractile regulation, suggesting the involvement of other elements. In this article we present evidence obtained from Triton X-100 detergent skinned and intact tissue which demonstrates that vascular smooth muscle contraction can be initiated by a Ca2+-dependent mechanism that does not require prior MLC phosphorylation. We show that Ca2+ can initiate contractions supported by cytidine triphosphate (CTP) and that these contractions are inhibited by calmodulin antagonists, suggesting a Ca2+–calmodulin dependence of force distinct from that for MLC phosphorylation. Evidence is presented to demonstrate that carotid medial fibers contain a mitogen-activated protein (MAP) kinase which is activated by Ca2+ and may catalyze caldesmon phosphorylation. Based in part on our results and those of other investigators, we propose that direct Ca2+–calmodulin binding to caldesmon or phosphorylation of caldesmon by a Ca2+-dependent MAP kinase disinhibits caldesmon. Disinhibition of caldesmon allows an inherent basal level of actin-activated myosin ATPase activity to be expressed. The result is the slow development of force.Key words: mitogen-activated protein kinase, caldesmon, Triton X-100, detergent-skinned fibers, cytidine triphosphate, calmodulin.

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