Bestrophin 4 (BEST4)

BEST4 belongs to the bestrophin family of anion channels, which includes BEST1, the gene mutant in vitelliform macular dystrophy (VMD), and 2 other BEST1-like genes, BEST2 and BEST3. Bestrophins are transmembrane (TM) proteins that share a homology region containing a high content of aromatic residues, including an invariant arg-phe-pro (RFP) motif. The bestrophin genes share a conserved gene structure, with almost identical sizes of the 8 RFP-TM domain-encoding exons and highly conserved exon-intron boundaries. Each of the 4 bestrophin genes has a unique 3-prime end of variable length. The open reading frame encodes a putative 473-amino acid protein with a calculated molecular weight of 53.5 kD. The expression of the gene was predominantly observed in colon and weakly in fetal brain, spinal cord, retina, lung, trachea, testis, and placenta.