Academic Thesis

Basic information

Name Takeya Kosuke
Belonging department
Occupation name
researchmap researcher code 5000068922
researchmap agency Okayama University of Science

Title

Ca2+ sensitization via phosphorylation of myosin phosphatase targeting subunit at threonine-855 by Rho kinase contributes to the arterial myogenic response

Bibliography Type

Joint Author

Author

Rosalyn P JOHNSON, Ahmed F EL-YAZBI,  Kosuke TAKEYA, Emma J WALSH, Michael P WALSH, William C COLE.

Summary

Ca(2+) sensitization has been postulated to contribute to the myogenic contraction of resistance arteries evoked by elevation of transmural pressure. However, the biochemical evidence of pressure-induced increases in phosphorylated myosin light chain phosphatase (MLCP) targeting subunit 1 (MYPT1) and/or 17 kDa protein kinase C (PKC)-potentiated protein phosphatase 1 inhibitor protein (CPI-17) required to sustain this view is not currently available. Here, we determined whether Ca(2+) sensitization pathways involving Rho kinase (ROK)- and PKC-dependent phosphorylation of MYPT1 and CPI-17, respectively, contribute to the myogenic response of rat middle cerebral arteries. ROK inhibitors (Y27632, 0.03-10 micromol l(-1); H1152, 0.001-0.3 micromol l(-1)) and PKC inhibitors (GF109203X, 3 micromol l(-1); Gö6976; 10 micromol l(-1)) suppressed myogenic vasoconstriction between 40 and 120 mmHg. An improved, highly sensitive 3-step Western blot method was developed for detection and quantification of MYPT1 and CPI-17 phosphorylation. Increasing pressure from 10 to 60 or 100 mmHg significantly increased phosphorylation of MYPT1 at threonine-855 (T855) and myosin light chain (LC(20)). Phosphorylation of MYPT1 at threonine-697 (T697) and CPI-17 were not affected by pressure. Pressure-evoked elevations in MYPT1-T855 and LC(20) phosphorylation were reduced by H1152, but MYPT1-T697 phosphorylation was unaffected. Inhibition of PKC with GF109203X did not affect MYPT1 or LC(20) phosphorylation at 100 mmHg. Our findings provide the first direct, biochemical evidence that a Ca(2+) sensitization pathway involving ROK-dependent phosphorylation of MYPT1 at T855 (but not T697) and subsequent augmentation of LC(20) phosphorylation contributes to myogenic control of arterial diameter in the cerebral vasculature. In contrast, suppression of the myogenic response by PKC inhibitors cannot be attributed to block of Ca(2+) sensitization mediated by CPI-17 or MYPT1 phosphorylation.    

Magazine(name)

Journal of Physiology.

Publisher

Volume

587

Number Of Pages

11

StartingPage

2537

EndingPage

2553

Date of Issue

2009/06

Referee

Exist

Invited

Language

English

Thesis Type

Research papers (academic journals)

ISSN

DOI

10.1113/jphysiol.2008.168252

NAID

PMID

19359365

URL

J-GLOBAL ID

arXiv ID

ORCID Put Code

DBLP ID