C2 Calcium Dependent Domain Containing Protein 2 (C2CD2)

C21orf25 encoded an N-terminally truncated 541-aa protein homologous to TMEM24. Complete coding sequence of C21orf25 was determined by assembling exons 1 and 2 within human genome sequence AP001745 and NM_199050.1 cDNA. Full-length C21orf25 encoded a 696-aa TMEM24-related protein with similar membrane topology. Exon-intron structure was conserved between TMEM24 and C21orf25 genes. TMEM24-ABCG4 locus at human chromosome 11q23.3 and C21orf25-ABCG1 locus at human chromosome 21q22.3 were paralogous regions with insertions of other genes due to recombination during evolution.TMEM. Human TMEM24, C21orf25 and their mouse homologs were type II transmembrane proteins with extracellular TM24H1 and TM24H2 domains. This is the first report on identification and characterization of the TMEM24 family.