Gene:
calbindin 2, 29kDa (calretinin)
Gene ID:
198538
Symbol:
CALB2
Species:
1000
Description:
Calbindin 2 (calretinin), closely related to calbindin 1, is an intracellular calcium-binding protein belonging to the troponin C superfamily. Calbindin 1 is known to be involved in the vitamin-D-dependent calcium absorption through intestinal and renal epithelia, while the function of neuronal calbindin 1 and calbindin 2 is poorly understood. The sequence of the calbindin 2 cDNA reveals an open reading frame of 271 codons coding for a protein of 31,520 Da, and shares 58% identical residues with human calbindin 1. Calbindin 2 contains five presumably active and one presumably inactive calcium-binding domains. Comparison with the partial sequences available for chick and guinea pig calbindin 2 reveals that the protein is highly conserved in evolution. The calbindin 2 message was detected in the brain, while absent from heart muscle, kidney, liver, lung, spleen, stomach and thyroid gland. There are two additional forms of alternatively spliced calbindin 2 mRNAs encoding C-terminally truncated proteins. Exon 7 can splice to exon 9, resulting in a frame shift and a translational stop at the second codon of exon 9, and encoding calretinin-20k. Exon 7 can also splice to exon 10, resulting in a frame shift and a translational stop at codon 15 of exon 10, and encoding calretinin-22k. The truncated proteins are able to bind calcium.