Autophosphorylation of Skeletal Muscle Myosin Light Chain Kinase

Z. H. Gao, J. T. Stull, C. R. Moomaw, J. Hsu, Clive A. Slaughter

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Ca2+/calmodulin-dependent myosin light chain kinase phosphorylates the regulatory light chain of myosin. Rabbit skeletal muscle myosin light chain kinase also catalyzes a Ca2+/calmodulin-dependent autophosphorylation with a rapid rate of incorporation of 1 mol of 32P/mol of kinase and a slower rate of incorporation up to 1.52 mol of 32P/mol. Autophosphorylation was inhibited by a peptide substrate that has a low Km value for myosin light chain kinase. Autophosphorylation at both rates was concentrationindependent, indicating an intramolecular mechanism. There were no significant changes in catalytic properties toward light chain and MgATP substrates or in calmodulin activation properties upon autophosphorylation. After digestion with V8 protease, phosphopeptides were purified and sequenced. Two phosphorylation sites were identified, Ser 160 and Ser 234, with the former associated with the rapid rate of phosphorylation. Both sites are located amino terminal of the catalytic domain. These results indicate that the extended “tail” region of the enzyme can fold into the active site of the kinase.

Original languageEnglish (US)
Pages (from-to)6126-6133
Number of pages8
JournalBiochemistry
Volume31
Issue number26
DOIs
StatePublished - Feb 1 1992

Fingerprint

Skeletal Muscle Myosins
Myosin-Light-Chain Kinase
Calmodulin
Phosphorylation
Catalytic Domain
Phosphotransferases
Phosphopeptides
Myosin Light Chains
Substrates
Tail
Digestion
Adenosine Triphosphate
Chemical activation
Rabbits
Light
Peptides
Enzymes

ASJC Scopus subject areas

  • Biochemistry

Cite this

Autophosphorylation of Skeletal Muscle Myosin Light Chain Kinase. / Gao, Z. H.; Stull, J. T.; Moomaw, C. R.; Hsu, J.; Slaughter, Clive A.

In: Biochemistry, Vol. 31, No. 26, 01.02.1992, p. 6126-6133.

Research output: Contribution to journalArticle

Gao, Z. H. ; Stull, J. T. ; Moomaw, C. R. ; Hsu, J. ; Slaughter, Clive A. / Autophosphorylation of Skeletal Muscle Myosin Light Chain Kinase. In: Biochemistry. 1992 ; Vol. 31, No. 26. pp. 6126-6133.
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