TY - JOUR
T1 - The heterodimer calmodulin
T2 - myosin light-chain kinase as a prototype vertebrate calcium signal transduction complex
AU - Kilhoffer, Marie Claude
AU - Lukas, Thomas J.
AU - Watterson, D. Martin
AU - Haiech, Jacques
N1 - Funding Information:
This work was supported in part by funds from N.I.H. Grant GM30861 (USA), Association pour la Recherche contre le Cancer (France) and the Centre National de Recherche Scientifique (France).
PY - 1992/11/10
Y1 - 1992/11/10
N2 - The heterodimer complex of calmodulin (CaM) and the protein kinase catalytic subunit of myosin light chain kinase from vertebrate smooth muscle and non-muscle tissues (sm/nmMLCK) is one of the most extensively characterized CaM-regulated enzyme complexes and it has an established in vivo role in the transduction of calcium signals into biological responses. We have used a combination of approaches to the study of CaM and sm/nmMLCK in order to derive initial insight into the key features of each protein and of the CaM-MLCK heterodimeric complex that are involved in protein-protein and calcium-protein recognition and regulation of enzyme activity. On-going studies are described here that include site-specific mutagenesis, fluorescence spectroscopy, enzymology and peptide analog analysis. These and previous results indicate that: (1), both electrostatic and hydrophobic features are important in the functionally correct interactions between CaM and MLCK; (2), even the interactions between CaM and peptide analogs of the CaM binding site of MLCK are heterogeneous and non-trivial in nature; (3), amino-acid residues that have been conserved in CaM across millions of years of evolution and that are conserved in CaMs with quantitative MLCK activator activity can be mutated without any detectable effect on activity and (4), structures different from the prototypical EF-hand domain of CaM can have similar calcium-binding activity in the presence of a CaM binding structure.
AB - The heterodimer complex of calmodulin (CaM) and the protein kinase catalytic subunit of myosin light chain kinase from vertebrate smooth muscle and non-muscle tissues (sm/nmMLCK) is one of the most extensively characterized CaM-regulated enzyme complexes and it has an established in vivo role in the transduction of calcium signals into biological responses. We have used a combination of approaches to the study of CaM and sm/nmMLCK in order to derive initial insight into the key features of each protein and of the CaM-MLCK heterodimeric complex that are involved in protein-protein and calcium-protein recognition and regulation of enzyme activity. On-going studies are described here that include site-specific mutagenesis, fluorescence spectroscopy, enzymology and peptide analog analysis. These and previous results indicate that: (1), both electrostatic and hydrophobic features are important in the functionally correct interactions between CaM and MLCK; (2), even the interactions between CaM and peptide analogs of the CaM binding site of MLCK are heterogeneous and non-trivial in nature; (3), amino-acid residues that have been conserved in CaM across millions of years of evolution and that are conserved in CaMs with quantitative MLCK activator activity can be mutated without any detectable effect on activity and (4), structures different from the prototypical EF-hand domain of CaM can have similar calcium-binding activity in the presence of a CaM binding structure.
KW - Calcium
KW - Calmodulin
KW - Fluorescence
KW - Mutagenesis
KW - Myosin light-chain kinase
KW - Protein kinase
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U2 - 10.1016/0167-4838(92)90033-A
DO - 10.1016/0167-4838(92)90033-A
M3 - Article
C2 - 1420336
AN - SCOPUS:0026462837
VL - 1160
SP - 8
EP - 15
JO - BBA - Protein Structure
JF - BBA - Protein Structure
SN - 1570-9639
IS - 1
ER -