Carboxyl terminal sequence of human phospholipase Cγ2

Abstract

Phospholipase C n 2 (PLC n 2), the predominant isoform of phospholipase C expressed in platelets, plays a major role in activation of platelets by collagen. Although PLC n 2 has been shown to be tyrosine phosphorylated upon collagen-induced activation, the phosphorylation sites are yet to be determined. We have sequenced the 3 ' terminal cDNA of human phospholipase C- n -2 and found it different from the human PLC n 2 cDNA sequence previously reported by Ohta et al . (Ohta S, Matsui A, Nazawa Y, Kagawa Y. FEBS Lett 1988; 242: 31-5). There is an extra guanosine at position 3723 which causes a shift in the reading frame. The new carboxyl terminal amino acid (aa) sequence beyond the frame shift is 88% identical to that of rat (21 out of 24 aa residues) which is considerably higher than the identity with published sequence (26% identity). The new deduced aa sequence contains two tyrosine residues at positions 1245 and 1264 which might be phosphorylated upon stimulation and hence might be important for the activation of the PLC n 2.