Characterization of the myosin light chain kinase from smooth muscle as an actin-binding protein that assembles actin filaments in vitro.
In addition to its kinase activity, myosin light chain kinase has an actin-binding activity, which results in bundling of actin filaments [Hayakawa et al., Biochem. Biophys. Res. Commun. 199, 786-791, 1994]. There are two actin-binding sites on the kinase: calcium- and calmodulin-sensitive and insensitive sites [Ye et al., J. Biol. Chem. 272, 32182-32189, 1997]. The calcium/calmodulin-sensitive, actin-binding site is located at Asp2-Pro41 and the insensitive site is at Ser138-Met213. The cyanogen bromide fragment, consisting of Asp2-Met213, is furnished with both sites and is the actin-binding core of myosin light chain kinase. Cross-linking between the two sites assembles actin filaments into bundles. Breaking of actin-binding at the calcium/calmodulin-sensitive site by calcium/calmodulin disassembles the bundles.
Hayakawa
K
K
Department of Pharmacology, Gunma University School of Medicine, Maebashi, Gunma 371-8511, Japan.
Okagaki
T
T
Ye
L H
LH
Samizo
K
K
Higashi-Fujime
S
S
Takagi
T
T
Kohama
K
K
D008841:Actin Cytoskeleton / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002147:Calmodulin / Q000737:chemistry; D002645:Chickens; D003488:Cyanogen Bromide; D005895:Gizzard, Avian; D008840:Microfilament Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000201:enzymology*; D009219:Myosin-Light-Chain Kinase / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D013861:Thiocyanates
D002147:Calmodulin; D008840:Microfilament Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D013861:Thiocyanates; C052523:actin filament bundling proteins; D009219:Myosin-Light-Chain Kinase; C008658:2-nitro-5-thiocyanobenzoic acid; D003488:Cyanogen Bromide