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
(all 22)
PubMed
8027085 Full text @ J. Biol. Chem.
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
Figures
No images available
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping
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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.