PUBLICATION
Delineation of two functionally distinct domains of cytosolic phospholipase A2, a regulatory Ca(2+)-dependent lipid-binding domain and a Ca(2+)-independent catalytic domain
- Authors
- Nalefski, E.A., Sultzman, L.A., Martin, D.M., Kriz, R.W., Towler, P.S., Knopf, J.L., and Clark, JD.
- ID
- ZDB-PUB-000817-2
- Date
- 1994
- Source
- The Journal of biological chemistry 269(27): 18239-18249 (Journal)
- Registered Authors
- Keywords
- none
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Binding Sites
- CHO Cells
- Calcium/metabolism*
- Catalysis
- Cell Line
- Chickens
- Cloning, Molecular
- Cricetinae
- Cytosol/enzymology
- Fishes
- Humans
- Lipid Metabolism*
- Mice
- Molecular Sequence Data
- Phospholipases A/chemistry*
- Phospholipases A/genetics
- Phospholipases A/metabolism*
- Phospholipases A2
- Sequence Homology, Amino Acid
- Substrate Specificity
- PubMed
- 8027085 Full text @ J. Biol. Chem.
Citation
Nalefski, E.A., Sultzman, L.A., Martin, D.M., Kriz, R.W., Towler, P.S., Knopf, J.L., and Clark, JD. (1994) Delineation of two functionally distinct domains of cytosolic phospholipase A2, a regulatory Ca(2+)-dependent lipid-binding domain and a Ca(2+)-independent catalytic domain. The Journal of biological chemistry. 269(27):18239-18249.
Abstract
Cytosolic phospholipase A2 (cPLA2) associates with natural membranes in response to physiological increases in Ca2+, resulting in the selective hydrolysis of arachidonyl phospholipids. The isolation and sequence analysis of cPLA2 cDNA clones from four different species revealed several highly conserved regions. The NH2-terminal conserved region is homologous to several other Ca(2+)-dependent lipid-binding proteins. Here we report that the first 178 residues of cPLA2, containing the homologous Ca(2+)-dependent lipid-binding (CaLB) motif, and another recombinant protein containing the cPLA2(1-178) fragment placed at the COOH terminus of the maltose-binding protein (MBP-CaLB) associate with membranes in a Ca(2+)-dependent manner. cPLA2 and MBP-CaLB also bind to synthetic liposomes at physiological Ca2+ concentrations, demonstrating that accessory proteins are not required. In contrast, delta C2, a truncated cPLA2 lacking the CaLB domain, fails to associate with membranes and fails to hydrolyze liposomal substrates. However, both delta C2 and cPLA2 hydrolyze monomeric 1-palmitoyl-2-lysophosphatidylcholine at identical rates in a Ca(2+)-independent fashion. These results delineate two functionally distinct domains of cPLA2, the Ca(2+)-independent catalytic domain, and the regulatory CaLB domain that presents the catalytic domain to the membrane in response to elevated Ca2+.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping