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 language | English (US) |
|---|---|
| Pages (from-to) | 26578-26582 |
| Number of pages | 5 |
| Journal | Journal of Biological Chemistry |
| Volume | 268 |
| Issue number | 35 |
| State | Published - Dec 15 1993 |
Fingerprint
ASJC Scopus subject areas
- Biochemistry
Cite this
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 journal › Article
}
TY - JOUR
T1 - A molecular mechanism for autoinhibition of myosin light chain kinases
AU - Gallagher, Patricia J.
AU - Herring, B. Paul
AU - Trafny, Andrzej
AU - Sowadski, Janusz
AU - Stull, James T.
PY - 1993/12/15
Y1 - 1993/12/15
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0027485728&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027485728&partnerID=8YFLogxK
M3 - Article
VL - 268
SP - 26578
EP - 26582
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 35
ER -