Like GalR2, the GalR3 receptor was first cloned from rat (Smith et al. 1998; Wang et al. 1997a). Rat GalR3 is a 370 amino acid protein, 36 per cent similar to rat GalR1, and with 55 per cent homology to rat GalR2. Human GalR3 was later cloned from a human genomic library, and was shown to encode a 368 amino acids long protein, sharing 90 per cent sequence identity with rat GalR3. Both rat and human GalR3 have a single consensus site for N-linked glycosylation, and several phosphate acceptor sites for intracellular protein kinase C phosporylation.
In humans, GalR3 is mapped to 22q12.2-13.1, and the mouse homologue is located on mouse chromosome 15 (Kolakowski et al. 1998). In similarity with GalR2, the gene for human GalR3 is interrupted by an intron. This intron is in GalR3 somewhat smaller than in the GalR2 gene, around 1 kb (Iismaa et al. 1998). The NH2-terminal and the first three TM domains are encoded by exon 1, and exon 2 encodes the remaining part of the receptor, that is, TM IV-VII and the COOH-terminal.
Was this article helpful?