Molecular characterization of cytosolic phospholipase A(2)-beta

We have isolated a cDNA encoding a 1012-amino acid polypeptide cPLA(2)-beta , that has significant homology with cPLA(2)-alpha in both the calcium-depe ndent lipid binding domain as well as in the catalytic domain. Transient ex pression of cPLA(2)-beta cDNA in COS cells results in an increase in calciu m-dependent phospholipase A(1) (PLA(1)) and PLA(2) activities compared with vector-transfected cells. cPLA(2)-beta is markedly less selective for clea vage at sn-2 as compared with cPLA(2)-alpha and cPLA(2)-gamma. Northern ana lysis reveals a cPLA(2)-beta transcript of 8 kilobase pairs that is express ed in all the human tissues examined. With the identification of cPLA(2)-be ta, the newly defined cPLA(2) family now comprises three members that may h ave dramatically different mechanisms for regulation of expression and enzy matic activation.