A molecular mechanism for autoinhibition of myosin light chain kinases

Patricia J. Gallagher, B. Paul Herring, Andrzej Trafny, Janusz Sowadski, James T. Stull

Research output: Contribution to journalArticle

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Abstract

It is postulated that basic residues within the inhibitory region of myosin light chain kinase (MLCK) bind acidic residues within the catalytic core to maintain the kinase in an inactive form. In this study, we identified residues within the catalytic cores of the skeletal and smooth muscle MLCKs that may bind basic residues in inhibitory region. Acidic residues within the catalytic core of the rabbit skeletal and smooth muscle MLCKs were mutated and the kinetic properties of the mutant kinases determined. Mutation of 6 and 8 acidic residues in the skeletal and smooth muscle MLCKs, respectively, result in mutant MLCKs with decreases in KCaM (the concentration of calmodulin required for half-maximal activation of myosin light chain kinase) value ranging from 2- to 100-fold. Two inhibitory domain binding residues identified in each kinase also bind a basic residue in light chain substrate. The remaining mutants all have wild-type Km values for light chain. The predicted inhibitory domain binding residues are distributed in a linear fashion across the surface of the lower lobe of the proposed molecular model of the smooth muscle MLCK catalytic core. As 6 of the inhibitory domain binding residues in the smooth muscle MLCK are conserved in other Ca2+/calmodulindependent protein kinases, the structural basis for autoinhibition and activation may be similar.

Original languageEnglish (US)
Pages (from-to)26578-26582
Number of pages5
JournalJournal of Biological Chemistry
Volume268
Issue number35
StatePublished - Dec 15 1993

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Myosin-Light-Chain Kinase
Catalytic Domain
Smooth Muscle Myosins
Smooth Muscle
Muscle
Skeletal Muscle
Phosphotransferases
Chemical activation
Light
Molecular Models
Calmodulin
Protein Kinases
Rabbits
Mutation
Kinetics
Substrates

ASJC Scopus subject areas

  • Biochemistry

Cite this

Gallagher, P. J., Herring, B. P., Trafny, A., Sowadski, J., & Stull, J. T. (1993). A molecular mechanism for autoinhibition of myosin light chain kinases. Journal of Biological Chemistry, 268(35), 26578-26582.

A molecular mechanism for autoinhibition of myosin light chain kinases. / Gallagher, Patricia J.; Herring, B. Paul; Trafny, Andrzej; Sowadski, Janusz; Stull, James T.

In: Journal of Biological Chemistry, Vol. 268, No. 35, 15.12.1993, p. 26578-26582.

Research output: Contribution to journalArticle

Gallagher, PJ, Herring, BP, Trafny, A, Sowadski, J & Stull, JT 1993, 'A molecular mechanism for autoinhibition of myosin light chain kinases', Journal of Biological Chemistry, vol. 268, no. 35, pp. 26578-26582.
Gallagher PJ, Herring BP, Trafny A, Sowadski J, Stull JT. A molecular mechanism for autoinhibition of myosin light chain kinases. Journal of Biological Chemistry. 1993 Dec 15;268(35):26578-26582.
Gallagher, Patricia J. ; Herring, B. Paul ; Trafny, Andrzej ; Sowadski, Janusz ; Stull, James T. / A molecular mechanism for autoinhibition of myosin light chain kinases. In: Journal of Biological Chemistry. 1993 ; Vol. 268, No. 35. pp. 26578-26582.
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