DOC2 - A NOVEL BRAIN PROTEIN HAVING 2 REPEATED C-2-LIKE DOMAINS

Two repeated C-2-like domains interacting with Ca2+ and phospholipid are found in synaptotagmin and Rabphilin-3A which are implicated in neurotransmitter release. Here we have isolated a cDNA encoding a novel protein having two repeated C-2-like domains from a human brain cDNA library. The isolated cDNA encodes a protein with 400 amino acids and a Mr of 44,071. The purified recombinant protein indeed interacts with Ca2+ and phospholipid. We have named this protein Doc2 (Double C-2). Doc2 is exclusively expressed in brain and is highly concentrated in the synaptic vesicle fraction. These results suggest that Doc2 is a novel brain protein and serves as a Ca2+ sensor in neurotransmitter release. (C) 1995 Academic Press, Inc.