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Phosphorylation of smooth muscle caldesmon by mitogen-activated protein (MAP) kinase and expression of MAP kinase in differentiated smooth muscle cells
- Source :
- The Journal of biological chemistry. 267(32)
- Publication Year :
- 1992
-
Abstract
- Smooth muscle caldesmon was phosphorylated in vitro by sea star p44mpk up to 2.0 mol of phosphate/mol of protein at both Ser and Thr residues. The phosphorylation sites were contained mainly in the COOH-terminal 10-kDa cyanogen bromide fragment which houses the binding sites for calmodulin, tropomyosin, and F-actin. Tryptic peptide maps of 32P-labeled caldesmon by p44mpk and p34cdc2 showed that while both enzymes recognized similar sites of phosphorylation, they have different preferred sites. Phosphorylation of caldesmon attenuated slightly its interaction with actin and had no effect on its binding to calmodulin and tropomyosin. Smooth muscle cell extracts from chicken gizzard and rat aorta contained 42- and 44-kDa proteins, respectively, which were cross-reactive with an antibody to sea star p44mpk. Immunoprecipitates from gizzard and aorta cell extracts, generated with the p44mpk antibody, possessed kinase activities toward myelin basic protein as well as caldesmon. These results suggest that MAP kinase may have functions in the differentiated smooth muscle cells distinct from those involved in the cell cycle.
- Subjects :
- Binding Sites
Molecular Sequence Data
Muscle, Smooth
Peptide Mapping
Chromatography, Affinity
Peptide Fragments
Kinetics
Mollusca
CDC2 Protein Kinase
Calcium-Calmodulin-Dependent Protein Kinases
Gizzard, Avian
Animals
Humans
Calmodulin-Binding Proteins
Amino Acid Sequence
Phosphorylation
Chickens
Protein Kinases
HeLa Cells
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 267
- Issue :
- 32
- Database :
- OpenAIRE
- Journal :
- The Journal of biological chemistry
- Accession number :
- edsair.pmid..........246e68b43d35d6fc1ae1a707bfec7d7e