Filamentous smooth muscle myosin is regulated by phosphorylation

doi:10.1083/jcb.109.6.2887

PeproTech: Your source for Cell Biology Research Reagents

This Article

	PDF (Full Text)
	Alert me when this article is cited
	Citation Map

Services

	Email this article
	Similar articles in this journal
	Similar articles in PubMed
	Alert me to new content in the JCB
	Download to citation manager

Citing Articles

	Citing Articles via HighWire
	Citing Articles via CrossRef
	Citing Articles via Google Scholar

Google Scholar

	Articles by Trybus, K. M.
	Search for Related Content

PubMed

	PubMed Citation
	Articles by Trybus, K. M.


Social Bookmarking

	What's this?

ARTICLES

Filamentous smooth muscle myosin is regulated by phosphorylation

KM Trybus
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254-9110.

The enzymatic activity of filamentous dephosphorylated smooth muscle myosin has been difficult to determine because the polymer disassembles to the folded conformation in the presence of MgATP. Monoclonal antirod antibodies were used here to "fix" dephosphorylated myosin in the filamentous state. The steady-state actin-activated ATPase of phosphorylated filaments was 30-100-fold higher than that of antibody- stabilized dephosphorylated filaments, suggesting that phosphorylation can activate ATPase activity independent of changes in assembly. The degree of regulation may exceed 100-fold, because steady-state measurements slightly overestimate the rate of product release from dephosphorylated filaments. Single-turnover experiments in the absence of actin showed that although dephosphorylated folded myosin released products at the low rate of 0.0005 s-1 (Cross, R. A., K. E. Cross, A. Sobieszek. 1986. EMBO [Eur. Mol. Biol. Organ.] J. 5:2637-2641) the rate of product release from dephosphorylated filaments was only 3-12-fold higher, depending on the ionic strength. The addition of actin did not increase this rate to any appreciable extent. Dephosphorylated filaments and dephosphorylated heavy meromyosin (Sellers, J. R. 1985. J. Biol. Chem. 260:15815-15819) thus have similar low rates of phosphate release both in the presence and absence of actin. These results show that light chain phosphorylation alone, without invoking other mechanisms, is an effective switch for regulating the activity of smooth muscle myosin filaments.
Add to CiteULike CiteULike Add to Complore Complore Add to Connotea Connotea Add to Del.icio.us Del.icio.us Add to Digg Digg Add to Reddit Reddit Add to Technorati Technorati What's this?

This article has been cited by other articles:

Leguillette, R., Zitouni, N. B., Govindaraju, K., Fong, L. M., Lauzon, A.-M. (2008). Affinity for MgADP and force of unbinding from actin of myosin purified from tonic and phasic smooth muscle. Am. J. Physiol. Cell Physiol. 295: C653-C660 [Abstract] [Full Text]
Gorodeski, G. I. (2007). Estrogen Modulation of MgATPase Activity of Nonmuscle Myosin-II-B Filaments. Endocrinology 148: 279-292 [Abstract] [Full Text]
Salzameda, B., Facemyer, K. C., Beck, B. W., Cremo, C. R. (2006). The N-terminal Lobes of Both Regulatory Light Chains Interact with the Tail Domain in the 10 S-inhibited Conformation of Smooth Muscle Myosin. J. Biol. Chem. 281: 38801-38811 [Abstract] [Full Text]
Takeya, K., Takahashi, M., Katoh, T., Yazawa, M. (2005). Asymmetric Photocross-Linking of Singly Phosphorylated Smooth Muscle Heavy Meromyosin. J Biochem 138: 245-253 [Abstract] [Full Text]
Zhang, H., Wessels, D., Fey, P., Daniels, K., Chisholm, R. L., Soll, D. R. (2002). Phosphorylation of the myosin regulatory light chain plays a role in motility and polarity during Dictyostelium chemotaxis. J. Cell Sci. 115: 1733-1747 [Abstract] [Full Text]
Halayko, A. J., Solway, J. (2001). Plasticity in Skeletal, Cardiac, and Smooth Muscle: Invited Review: Molecular mechanisms of phenotypic plasticity in smooth muscle cells. J. Appl. Physiol. 90: 358-368 [Abstract] [Full Text]
Liang, W., Warrick, H. M., Spudich, J. A. (1999). A Structural Model for Phosphorylation Control of Dictyostelium Myosin II Thick Filament Assembly. J. Cell Biol. 147: 1039-1048 [Abstract] [Full Text]
Woodrum, D. A., Brophy, C. M., Wingard, C. J., Beall, A., Rasmussen, H. (1999). Phosphorylation events associated with cyclic nucleotidedependent inhibition of smooth muscle contraction. Am. J. Physiol. Heart Circ. Physiol. 277: H931-H939 [Abstract] [Full Text]
Rovner, A. S. (1998). A Long, Weakly Charged Actin-binding Loop Is Required for Phosphorylation-dependent Regulation of Smooth Muscle Myosin. J. Biol. Chem. 273: 27939-27944 [Abstract] [Full Text]
Malmqvist, U., Trybus, K. M., Yagi, S., Carmichael, J., Fay, F. S. (1997). Slow cycling of unphosphorylated myosin is inhibited by calponin, thus keeping smooth muscle�relaxed. Proc. Natl. Acad. Sci. USA 94: 7655-7660 [Abstract] [Full Text]
Sata, M., Stafford, W.�F. III, Mabuchi, K., Ikebe, M. (1997). The motor domain and the regulatory domain of myosin solely dictate enzymatic activity and phosphorylation-dependent regulation,�respectively. Proc. Natl. Acad. Sci. USA 94: 91-96 [Abstract] [Full Text]
Olney, J. J., Sellers, J. R., Cremo, C. R. (1996). Structure and Function of the 10S Conformation of Smooth Muscle Myosin. J. Biol. Chem. 271: 20375-20384 [Abstract] [Full Text]
Cremo, C. R., Sellers, J. R., Facemyer, K. C. (1995). Two Heads Are Required for Phosphorylation-dependent Regulation of Smooth Muscle Myosin. J. Biol. Chem. 270: 2171-2175 [Abstract] [Full Text]
Cremo, C. R., Wang, F., Facemyer, K., Sellers, J. R. (2001). Phosphorylation-dependent Regulation Is Absent in a Nonmuscle Heavy Meromyosin Construct with One Complete Head and One Head Lacking the Motor Domain. J. Biol. Chem. 276: 41465-41472 [Abstract] [Full Text]