Myosin phosphatase: Structure, regulation and function

M, Ito; Nakano, Takeshi; Erdõdi, Ferenc; Hartshorne, David J.

doi:10.1023/b:mcbi.0000021373.14288.00

Cited by 407 publications

(402 citation statements)

References 109 publications

Supporting

Mentioning

386

Contrasting

Order By: Relevance

“…MYPT-1 phosphorylation by Rho kinase decreases the activity of myosin phosphatase, thereby resulting in increased myosin L chain phosphorylation and actin-myosin interaction (30). The activity of JNK, p38, AKT, and MKK4 was evaluated by measuring the amount of phosphorylated and active form of these kinases: phosphorylated JNK (threonine 183/tyrosine 185), p38 (threonine 180/tyrosine 182), AKT (serine 473), and MKK4 (serine 257/threonine 261) (Cell Signaling).…”

Section: Immunoblottingmentioning

confidence: 99%

“…Rho kinase in turn phosphorylates its substrates such as MYPT-1 at threonine 696 and 853. Phosphorylation of MYPT-1 inactivates myosin L chain phosphatase, leading to myosin L chain phosphorylation, cytoskeletal reorganization, and stress fiber formation (30). To determine whether Rho kinase is also activated by TNF-␣, the phosphorylation state of MYPT-1 was measured.…”

Section: Tnf-␣ Induces Activation Of Rhoa and Rho Kinase In Human Pulmentioning

confidence: 99%

See 1 more Smart Citation

Activation of Rho Kinase by TNF-α Is Required for JNK Activation in Human Pulmonary Microvascular Endothelial Cells

Mong

Petrulio

Kaufman

et al. 2008

The Journal of Immunology

View full text Add to dashboard Cite

TNF‐α induces complex signaling events in endothelial cells (ECs), resulting in gene transcription and increased junctional permeability. This study examined the activation of the RhoA/Rho kinase pathway induced by TNF‐α in primary human pulmonary microvascular ECs and its role in EC responses to TNF‐α. Activation of RhoA was induced by TNF‐α within five minutes. This increase in RhoA activity rapidly decreased, and a late activation of RhoA was induced three hours after TNF‐α treatment. This late but not early RhoA activation was associated with its accumulation in focal aggregates near EC edges. TNF‐α also induced Rho kinase activation that was observed within five minutes and lasted for at least three hours. Inhibition of Rho kinase prevented TNF‐α‐induced cytoskeletal changes and permeability increases. TNF‐α also induced activation of JNK that peaked at fifteen minutes and lasted for at least three hours, and inhibition of Rho kinase prevented TNF‐α‐induced early and late JNK activation. Inhibition of JNK activation, however, did not prevent TNF‐α‐induced cytoskeletal changes, suggesting that Rho kinase did not modulate cytoskeletal changes through JNK activation. These data demonstrate that RhoA/Rho kinase pathway is rapidly activated by TNF‐α and regulates several downstream responses that include JNK activation, cytoskeletal changes and increases in permeability. Supported by NIH HL070009.

show abstract

Section: Immunoblottingmentioning

confidence: 99%

Section: Tnf-␣ Induces Activation Of Rhoa and Rho Kinase In Human Pulmentioning

confidence: 99%

Activation of Rho Kinase by TNF-α Is Required for JNK Activation in Human Pulmonary Microvascular Endothelial Cells

Mong

Petrulio

Kaufman

et al. 2008

The Journal of Immunology

View full text Add to dashboard Cite

show abstract

“…The effects of RhoA on the Ca 2ϩ sensitivity of contraction have been ascribed to its role in regulating the catalytic activity of smooth muscle myosin light chain (MLC) phosphatase (23,33,47,53). MLC phosphatase activity can be regulated by the downstream RhoA effector, Rho kinase (ROCK), which can inhibit MLC phosphatase by phosphorylating and inhibiting activity of its regulatory subunit, myosin phosphatase subunit 1 (MYPT1), or by phosphorylating the inhibitory peptide of MLC phosphatase, CPI-17 (27,47). The inhibition of MLC phosphatase results in the augmentation of agonist-induced MLC phosphorylation, which has been proposed as a mechanism for increasing smooth muscle contractility (19,30,47,53).…”

mentioning

confidence: 99%

The effects of the small GTPase RhoA on the muscarinic contraction of airway smooth muscle result from its role in regulating actin polymerization

Zhang

Gunst

2010

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

Zhang W, Du L, Gunst SJ. The effects of the small GTPase RhoA on the muscarinic contraction of airway smooth muscle result from its role in regulating actin polymerization. Am J Physiol Cell Physiol 299: C298 -C306, 2010. First published May 5, 2010 doi:10.1152/ajpcell.00118.2010.-The small GTPase RhoA increases the Ca 2ϩ sensitivity of smooth muscle contraction and myosin light chain (MLC) phosphorylation by inhibiting the activity of MLC phosphatase. RhoA is also a known regulator of cytoskeletal dynamics and actin polymerization in many cell types. In airway smooth muscle (ASM), contractile stimulation induces MLC phosphorylation and actin polymerization, which are both required for active tension generation. The objective of this study was to evaluate the primary mechanism by which RhoA regulates active tension generation in intact ASM during stimulation with acetylcholine (ACh). RhoA activity was inhibited in canine tracheal smooth muscle tissues by expressing the inactive RhoA mutant, RhoA T19N, in the intact tissues or by treating them with the cell-permeant RhoA inhibitor, exoenzyme C3 transferase. RhoA inactivation reduced ACh-induced contractile force by ϳ60% and completely inhibited ACh-induced actin polymerization but inhibited ACh-induced MLC phosphorylation by only ϳ20%. Inactivation of MLC phosphatase with calyculin A reversed the reduction in MLC phosphorylation caused by RhoA inactivation, but calyculin A did not reverse the depression of active tension and actin polymerization caused by RhoA inactivation. The MLC kinase inhibitor, ML-7, inhibited ACh-induced MLC phosphorylation by ϳ80% and depressed active force by ϳ70% but did not affect ACh-induced actin polymerization, demonstrating that AChstimulated actin polymerization occurs independently of MLC phosphorylation. We conclude that the RhoA-mediated regulation of ACh-induced contractile tension in ASM results from its role in mediating actin polymerization rather than from effects on MLC phosphatase or MLC phosphorylation. cytoskeleton; calcium sensitization; myosin light chain phosphorylation; myosin light chain phosphatase; myosin phosphatase; calyculin A; myosin light chain kinase

show abstract

“…Given that MYPT1 regulates MP activity, 3 the effects of decreased MYPT1 expression on contraction and relaxation of aortic rings were examined. The aortic rings of 20-weekold apoE-KO mice and B6 mice were stimulated with the a 1 -adrenoceptor agonist phenylephrine and thromboxane A 2 analog U46619.…”

Section: Mypt1 Downregulation Contributes To Abnormal Contraction Andmentioning

confidence: 99%

“…The phosphorylation of MYPT1 by protein kinases is a major regulatory mechanism for MP that results in either the inhibition or enhancement of MP activity. 3 Small GTPase RhoA and its effecter, Rho-kinase, inhibit MP activity through MYPT1 phosphorylation, 4 and mediate calcium sensitization of smooth muscle contraction. 5 In contrast, relaxation of smooth muscle results from nitric oxide (NO)-stimulated activation of MP, which is mediated by cGMP and cGMP-dependent protein kinase (PKG).…”

mentioning

confidence: 99%

ROS-mediated downregulation of MYPT1 in smooth muscle cells: a potential mechanism for the aberrant contractility in atherosclerosis

Cheng

Tsai

et al. 2013

Laboratory Investigation

View full text Add to dashboard Cite

Reactive oxygen species (ROS) mediates the aberrant contractility in hypertension. Abnormal contractility occurs in atherosclerotic vessels but changes in proteins that regulate contractility remain poorly understood. Myosin phosphatase (MP) activity, which regulates smooth muscle relaxation, is regulated by the phosphorylation of its regulatory subunit, MP targeting subunit 1 (MYPT1). In the present study, we examined the roles of ROS in MP subunit expression both in cultured human aortic smooth muscle cells (HASMCs) and during atherosclerosis progression in apolipoprotein E-knockout (apoE-KO) mice. Furthermore, the effect of decreased MYPT1 on actin cytoskeleton and cell migration activity was assessed in HASMCs. Short hairpin RNA-mediated knockdown of MYPT1 increased stress fibers and attenuated platelet-derived growth factor-induced cell migration in HASMCs. Superoxide anion-inducing agent LY83583 downregulated MYPT1 mRNA and protein levels, but did not affect the phosphorylation of MYPT1 and catalytic subunit of MP, PP1d. The LY83583-induced decrease in MYPT1 was abolished by co-treating with superoxide dismutase or by inhibiting NADPH oxidase with diphenyleneiodonium. Treatment of peroxynitrite, but not hydrogen peroxide (H 2 O 2 ), downregulated MYPT1 protein expression and induced MYPT1 phosphorylation without affecting mRNA levels. Co-treatment with a proteasome inhibitor, MG-132, eliminated peroxynitrite-induced MYPT1 downregulation. In apoE-KO mice, MYPT1 protein, but not mRNA, levels were markedly decreased in 16-week-and 24-week-old mice. Oral estrogen treatment, which was previously shown to decrease aortic ROS levels, upregulated aortic MYPT1 expression. Moreover, reduction in MYPT1 expression correlated with increased aortic sensitivity toward vasoconstrictors. These results suggested that during atherosclerosis progression oxidative stress mediates the downregulation of MYPT1, which may inhibit smooth muscle cell migration and contribute to the aberrant contractility.Laboratory Investigation (2013) 93, 422-433; doi:10.1038/labinvest.2013 published online 18 February 2013 KEYWORDS: atherosclerosis; contractility; myosin phosphatase; reactive oxygen species; smooth muscle At the molecular level, phosphorylation of the 20-kDa myosin light chains (MLC 20 ) is a key determinant for smooth muscle contraction. MLC 20 phosphorylation levels are determined by the activity ratio between myosin light chain kinase (MLCK) and myosin phosphatase (MP). 1 Although MLCK activation depends on cytoplasmic calcium concentration, MP activity is subject to modulation by various signaling molecules. 2 MP is a heterotrimer comprised of a 37-to 38-kDa catalytic subunit (PP1d), a 110-to 130-kDa regulatory subunit (MP targeting subunit 1; MYPT1), and a 20-kDa subunit of unknown function. The phosphorylation of MYPT1 by protein kinases is a major regulatory mechanism for MP that results in either the inhibition or enhancement of MP activity. 3 Small GTPase RhoA and its effecter, Rho-kinase, inhibit MP activity through ...

show abstract

Myosin phosphatase: Structure, regulation and function

Cited by 407 publications

References 109 publications

Activation of Rho Kinase by TNF-α Is Required for JNK Activation in Human Pulmonary Microvascular Endothelial Cells

Activation of Rho Kinase by TNF-α Is Required for JNK Activation in Human Pulmonary Microvascular Endothelial Cells

The effects of the small GTPase RhoA on the muscarinic contraction of airway smooth muscle result from its role in regulating actin polymerization

ROS-mediated downregulation of MYPT1 in smooth muscle cells: a potential mechanism for the aberrant contractility in atherosclerosis

Contact Info

Product

Resources

About