A splice variant of arrestin from human retina.

Retinal arrestin is known to participate in the quenching of phototransduction through binding to light-activated and phosphorylated rhodopsin. Recently, a splice variant of retinal arrestin was identified in bovine photoreceptors which could bind unphosphorylated photoactive rhodopsin. In this report, a splice variant of retinal arrestin is identified in the human retina. The variant of human arrestin is produced by splicing out exon 12, unlike the bovine variant which is produced by splicing out exon 16. This 78 bp deletion in the human splice variant produces a polypeptide with a calculated molecular weight of 42.2 kDa that lacks 26 amino acids when compared to the full-length retinal arrestin. The use of quantitative competitive PCR indicates that the mRNA for the human splice variant of arrestin is present at approximately one-twentieth of the level of human arrestin mRNA.