There are at least two proteinisoforms of the Double C2 protein, namely alpha (DOC2A) and beta (DOC2B), which contain two C2-like domains. DOC2A and DOC2B are encoded by different genes; these genes are at times confused with the unrelated DAB2 gene which was initially named DOC-2. Doc2b enhances Ca(2+)-dependentexocytosis inadipocytes,[7]chromaffin cells of theadrenal gland[8] andbeta cells in the pancreas.[9] In the central nervous system, Doc2b contributes to the spontaneous release ofneurotransmitters, which was thought to be acting as a high-affinity Ca(2+) sensor for exocytosis ofsynaptic vesicles[10] However, further work has shown that while DOC2b is both important for spontaneous exocytosis ofsynaptic vesicles and bindsCalcium, it does not in fact change the calcium dependence of spontaneoussynaptic vesicle release and thus can not be the calcium sensor for this process.[11]
^"Human PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
^Orita S, Sasaki T, Naito A, Komuro R, Ohtsuka T, Maeda M, Suzuki H, Igarashi H, Takai Y (Feb 1995). "Doc2: a novel brain protein having two repeated C2-like domains".Biochem Biophys Res Commun.206 (2):439–48.doi:10.1006/bbrc.1995.1062.PMID7826360.
^Miyazaki M, Emoto M, Fukuda N, Hatanaka M, Taguchi A, Miyamoto S, Tanizawa Y (Jul 2009). "DOC2b is a SNARE regulator of glucose-stimulated delayed insulin secretion".Biochem Biophys Res Commun.384 (4):461–5.doi:10.1016/j.bbrc.2009.04.133.PMID19410553.
Sakaguchi G, Orita S, Maeda M, Igarashi H, Takai Y (1996). "Molecular cloning of an isoform of Doc2 having two C2-like domains".Biochem. Biophys. Res. Commun.217 (3):1053–61.doi:10.1006/bbrc.1995.2876.PMID8554557.
