Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.
Science Career Fair

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Sci. STKE, 23 November 1999
Vol. 1999, Issue 9, p. tw7
[DOI: 10.1126/stke.1999.9.tw7]

EDITORS' CHOICE

MUSCLE CONTRACTION Maintaining Smooth Muscle Tone

Abstract: Contraction of smooth muscle cells, such as those that line blood vessels, is regulated through phosphorylation of the myosin light chain. Phosphorylation by myosin light-chain kinase (and consequent increased contraction) is opposed by dephosphorylation (and consequent relaxation) catalyzed by the myosin light-chain phosphatase (PP1M). Some agents that control blood pressure act by modulating this regulatory system. Nitric oxide, a vasodilator, causes increased intracellular production of cyclic guanosine monophosphate (cGMP), which in turn activates cGMP-dependent protein kinase (cGKI{alpha}). Surks et al. provide evidence that cGKI{alpha} localizes as part of a multienzyme complex at the contractile apparatus through direct interaction with the myosin-binding subunit (MBS) of PP1M. This association was required for cGMP-dependent activation of PP1M and dephosphorylation of myosin light chain. The CGKI{alpha} enzyme adds yet another component to the cluster of regulatory components bound to the MBS, which includes the catalytic subunit of PP1M and another protein kinase, Rho-associated kinase, which has an opposite (inhibitory) action on PP1M.

Surks, H.K., Mochizuki, N., Kasai, Y., Georgescu, S.P., Tang, K.M., Ito, M., Lincoln, T.M., and Mendelsohn, M.D. (1999) Regulation of myosin phosphatase by a specific interaction with cGMP- dependent protein kinase I{alpha}. Science 286: 1583-1587. [Abstract] [Full Text]

Citation: Maintaining Smooth Muscle Tone. Sci. STKE 1999, tw7 (1999).

Read the Full Text

ADVERTISEMENT
Click Me!

ADVERTISEMENT
Click Me!

To Advertise     Find Products

Science Signaling. ISSN 1937-9145 (pre-2008: Science's STKE. ISSN 1525-8882)