Extracellular ATP induces assembly and activation of the myosin light chain phosphatase complex in endothelial cells☆

Härtel, Frauke V.; Rodewald, Christoph Walter; Aslam, Muhammad; Gündüz, Dursun; Hafer, Laurie J.; Neumann, Joachim; Piper, Hans Michael; Noll, Thomas

doi:10.1016/j.cardiores.2007.02.013

Cited by 19 publications

(12 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We found that Calyculin A induced an increase in MYPT1 phosphorylation at Thr-853, which is a phosphorylation site of Rho-kinase ( Figure 2A ) . These results indicate that MYPT1 is dephosphorylated by PP1 or PP2A, in agreement with previous reports [22]–[24]. It is known that a 17 kDa protein kinase C (PKC)-potentiated phosphatase inhibitory protein (CPI-17), phosphorylated at Thr-38, interacts with a catalytic subunit of myosin phosphatase and suppresses myosin phosphatase activity [28].…”

Section: Resultssupporting

confidence: 92%

“…It is likely that myosin phosphatase controls phosphorylation of MYPT1 at Thr-696 or Thr-853. Furthermore, Calyculin A, an inhibitor of PP1 and PP2A, increases the phosphorylation of MYPT1 at Thr-696 and Thr-853 in vivo [22]–[24]. We confirmed that treatment with Calyculin A induced the phosphorylation of MYPT1 at Thr-853 ( Figure 2A ) .…”

Section: Discussionsupporting

confidence: 74%

“…Since MYPT1 is also a substrate of Rho-kinase, it is possible that myosin phosphatase undergoes auto-dephosphorylation following phosphorylation by Rho-kinase. In fact, the phosphatase inhibitor Calyculin A, which suppresses the activity of protein phosphatase 1 (PP1) and 2A (PP2A), accelerates the phosphorylation of MYPT1 [22]–[24]. Kimura and colleagues have reported the direct dephosphorylation of MYPT1 by myosin phosphatase in vitro in the following experiment: in an in vitro phosphatase assay using purified myosin phosphatase, Rho-kinase, and MLC, they found that the purified myosin phosphatase holoenzyme directly dephosphorylates its regulatory subunit, MYPT1, which has been phosphorylated by Rho-kinase [25].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dynamic Regulation of Myosin Light Chain Phosphorylation by Rho-kinase

et al. 2012

View full text Add to dashboard Cite

Myosin light chain (MLC) phosphorylation plays important roles in various cellular functions such as cellular morphogenesis, motility, and smooth muscle contraction. MLC phosphorylation is determined by the balance between activities of Rho-associated kinase (Rho-kinase) and myosin phosphatase. An impaired balance between Rho-kinase and myosin phosphatase activities induces the abnormal sustained phosphorylation of MLC, which contributes to the pathogenesis of certain vascular diseases, such as vasospasm and hypertension. However, the dynamic principle of the system underlying the regulation of MLC phosphorylation remains to be clarified. Here, to elucidate this dynamic principle whereby Rho-kinase regulates MLC phosphorylation, we developed a mathematical model based on the behavior of thrombin-dependent MLC phosphorylation, which is regulated by the Rho-kinase signaling network. Through analyzing our mathematical model, we predict that MLC phosphorylation and myosin phosphatase activity exhibit bistability, and that a novel signaling pathway leading to the auto-activation of myosin phosphatase is required for the regulatory system of MLC phosphorylation. In addition, on the basis of experimental data, we propose that the auto-activation pathway of myosin phosphatase occurs in vivo. These results indicate that bistability of myosin phosphatase activity is responsible for the bistability of MLC phosphorylation, and the sustained phosphorylation of MLC is attributed to this feature of bistability.

show abstract

Section: Resultssupporting

confidence: 92%

Section: Discussionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dynamic Regulation of Myosin Light Chain Phosphorylation by Rho-kinase

et al. 2012

View full text Add to dashboard Cite

show abstract

“…There is a growing body of evidence that myosin-light-chain (MLC) kinase (MLCK) and phosphatase (MLCP) participate in the regulation of endothelial barrier function (Kolosova et al, 2005; Satpathy et al, 2005; Hartel FV et al, 2007). Conventional MLCP consist of a catalytic protein phosphatase 1 (PP1c) subunit, a myosin phosphatase targeting subunit (MYPT1), and a smaller M20 subunit, not always present in all the phosphatase complexes (Tar et al, 2006, Hartshorne et al, 1998; Takizawa et al, 2003; Ito et al, 2004).…”

Section: Resultsmentioning

confidence: 99%

Molecular mechanisms involved in adenosine-induced endothelial cell barrier enhancement

Umapathy¹,

Zheng²,

Zemskov³

et al. 2010

Vascular Pharmacology

View full text Add to dashboard Cite

Extracellular adenosine is a physiologically relevant agonist released by various sources, including endothelial cells (EC) and activated platelets, with complex effects mediated via activation of P1 purinergic receptors. Adenosine-induced EC production of glutathione peroxidase1 and nitric oxide is recognized, and an anti-inflammatory mechanism has been described. Effects of extracellular adenosine on the pulmonary EC barrier function and vascular permeability, however, remain poorly characterized. In this study, we demonstrated the adenosine-induced rapid dose-dependent barrier enhancement in human pulmonary artery EC (HPAEC) as measured by an increase in transendothelial electrical resistance (TER). We have shown that HPAEC express only A2A and A2B adenosine receptors. Pharmacological and siRNA depletion studies indicate that A2A, but not A2B receptor activation is required for the adenosine-induced TER increase. Depletion of Gαs with a specific siRNA significantly attenuated the adenosine-induced TER response in HPAEC. In contrast, depletion of either Gαq or Gαi2 did not affect the adenosine-induced TER increase. This suggests that the adenosine-induced TER increase is cAMP-dependent. The adenosine-induced barrier enhancement effects were associated with a rearrangement of the EC F-actin component of the cytoskeleton, enhanced cell surface presentation of cell-cell junctional protein VE-cadherin and an involvement of Myosin-light-chain phosphatase (MLCP). Our results suggest, for the first time, that adenosine regulates the EC barrier function via A2A receptors followed by Gαs engagement and is associated with cytoskeletal activation.

show abstract

“…Potential mechanisms for the PPP1 family include modulation of vascular permeability, cytoskeletal structure, and filopodia extension. PPP2A has been implicated in endothelial migration (Hartel et al, 2007; Li et al, 2007; Shinoki et al, 1995; Young et al, 2002). Moreover, Cantharidin, the 2, 3-dimethylanhydride of Endothall, has been shown to enhance endothelial-mediated contraction of arteries and endothelial permeability (Knapp et al, 1999, 2000).…”

Section: Discussionmentioning

confidence: 99%

Combination of Reverse and Chemical Genetic Screens Reveals Angiogenesis Inhibitors and Targets

Kalén

Wallgard

Asker³

et al. 2009

Chemistry & Biology

View full text Add to dashboard Cite

SUMMARY We combined reverse and chemical genetics to identify targets and compounds modulating blood vessel development. Through transcript profiling in mice, we identified 150 potentially druggable microvessel-enriched gene products. Orthologs of 50 of these were knocked down in a reverse genetic screen in zebrafish, demonstrating that 16 were necessary for developmental angiogenesis. In parallel, 1280 pharmacologically active compounds were screened in a human cell-based assay, identifying 28 compounds selectively inhibiting endothelial sprouting. Several links were revealed between the results of the reverse and chemical genetic screens, including the serine/threonine (S/T) phosphatases ppp1ca, ppp1cc, and ppp4c and an inhibitor of this gene family; Endothall. Our results suggest that the combination of reverse and chemical genetic screens, in vertebrates, is an efficient strategy for the identification of drug targets and compounds that modulate complex biological systems, such as angiogenesis.

show abstract

Extracellular ATP induces assembly and activation of the myosin light chain phosphatase complex in endothelial cells☆

Abstract: The present study shows for the first time that, in endothelial cells, extracellular ATP causes activation of MLCP through recruitment of PP1delta and MYPT1 into a MLCP holoenzyme complex and PP1-mediated reduction of the inhibitory phosphorylation of MYPT1.

Cited by 19 publications

References 37 publications

Dynamic Regulation of Myosin Light Chain Phosphorylation by Rho-kinase

Dynamic Regulation of Myosin Light Chain Phosphorylation by Rho-kinase

Molecular mechanisms involved in adenosine-induced endothelial cell barrier enhancement

Combination of Reverse and Chemical Genetic Screens Reveals Angiogenesis Inhibitors and Targets

Contact Info

Product

Resources

About