Role of Protein Phosphatase Type 1 in Contractile Functions: Myosin Phosphatase

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

doi:10.1074/jbc.r400018200

Cited by 207 publications

(224 citation statements)

References 55 publications

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“…MLCP is a heterotrimer that consists of a catalytic type 1 phosphatase subunit (PP1c␦), a regulatory subunit, MYPT1, and a 20-KDa subunit (M20) with unknown function (14,15). MYPT1 enhances the catalytic activity and specificity of PP1c␦ toward phosphorylated RLC in its binding to myosin (16).…”

mentioning

confidence: 99%

Myosin Phosphatase Target Subunit 1 (MYPT1) Regulates the Contraction and Relaxation of Vascular Smooth Muscle and Maintains Blood Pressure

Qiao

Chen

et al. 2014

Journal of Biological Chemistry

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Background: MYPT1 is a regulatory subunit of myosin phosphatase. Results: Deleting MYPT1 in vascular smooth muscle enhances myosin phosphorylation, contractility, and blood pressure. Conclusion: Genetic evidence shows MYPT1 plays a role in modulating vascular smooth muscle contractility. Significance: Although MYPT1 is not essential for vascular smooth muscle contractility, it contributes to blood pressure maintenance in vivo through signaling to myosin phosphorylation.

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mentioning

confidence: 99%

Myosin Phosphatase Target Subunit 1 (MYPT1) Regulates the Contraction and Relaxation of Vascular Smooth Muscle and Maintains Blood Pressure

Qiao

Chen

et al. 2014

Journal of Biological Chemistry

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“…MLCK is also capable of phosphorylating LC 20 at Thr 18 in vitro, but this requires very high (unphysiological) concentrations of the kinase (4,5). Relaxation follows the removal of Ca 2ϩ from the cytosol, which inactivates MLCK, and myosin is dephosphorylated by myosin light chain phosphatase (MLCP), a type 1 Ser/Thr phosphatase (6).…”

mentioning

confidence: 99%

Myosin Regulatory Light Chain Diphosphorylation Slows Relaxation of Arterial Smooth Muscle

Sutherland

Walsh

2012

Journal of Biological Chemistry

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“…The presence of MLCP in hair cells has not been reported. Therefore, in order to test whether MLCP is active in RAPHCs, we took advantage of the fact that the catalytic subunit of the MLCP is a type 1 protein phosphatase (PP1, Hartshorne et al, 2004). A hallmark of PP1 is its much higher susceptibility to inhibition by calyculin A, than by okadaic acid (Ishihara et al, 1989).…”

Section: Discussionmentioning

confidence: 99%

“…However, the level of phosphorylation of the MLC is determined by the opposing effects of MLCK and MLCP. The catalytic subunit of MLCP is a type 1 phosphatase (PP1) (for a review see Hartshorne et al, 2004)). Thus, we tested the effect of two PP1 inhibitors, known to inhibit the smooth muscle myosin phosphatase activity (Ishihara et al, 1989), on the RAPHCs' shape, as well as on the response to ionomycin.…”

Section: Myosin Light Chain Phosphatase (Mlcp)mentioning

confidence: 99%

Slow motility in hair cells of the frog amphibian papilla: Myosin light chain-mediated shape change

Farahbakhsh

Narins

2008

Hearing Research

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Using video, fluorescence and confocal microscopy, quantitative analysis and modeling, we investigated intracellular processes mediating the calcium/calmodulin (Ca 2+ /CaM)-dependent slow motility in hair cells dissociated from the rostral region of amphibian papilla, one of the two auditory organs in frogs. The time course of shape changes in these hair cells during the period of pretreatment with several specific inhibitors, as well as their response to the calcium ionophore, ionomycin, were recorded and compared. These cells respond to ionomycin with a tri-phasic shape change: an initial phase of iso-volumetric length decrease; a period of concurrent shortening and swelling; and the final phase of increase in both length and volume. We found that both the myosin light chain kinase inhibitor, ML-7, and antagonists of the multifunctional Ca 2+ /CaM-dependent kinases, KN-62 and KN-93, inhibit the iso-volumetric shortening phase of the response to ionomycin. The type 1 protein phosphatase inhibitors, calyculin A and okadaic acid induce minor shortening on their own, but do not significantly alter the phase 1 response. However, they appear to counter effects of the inhibitors of Ca 2+ /CaM-dependent kinases. We hypothesize that an active actomyosin-based process mediates the iso-volumetric shortening in the frog rostral amphibian papillar hair cells.

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Role of Protein Phosphatase Type 1 in Contractile Functions: Myosin Phosphatase

Cited by 207 publications

References 55 publications

Myosin Phosphatase Target Subunit 1 (MYPT1) Regulates the Contraction and Relaxation of Vascular Smooth Muscle and Maintains Blood Pressure

Myosin Phosphatase Target Subunit 1 (MYPT1) Regulates the Contraction and Relaxation of Vascular Smooth Muscle and Maintains Blood Pressure

Myosin Regulatory Light Chain Diphosphorylation Slows Relaxation of Arterial Smooth Muscle

Slow motility in hair cells of the frog amphibian papilla: Myosin light chain-mediated shape change

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