Background information
The Bestrophins are a newly described family of anion channels unrelated in primary sequence to any previously characterized channel proteins. Bestrophins were originally defined as a family of over 20 related sequences of the C. elegans. The first mammalian Bestrophin was identified as the vitelliform macular dystrophy (VMD), 1 also known as Best disease. Three more members of the bestrophin family members were cloned and indentified recently, Bestrophin 2, 3 and 4. RT PCR analyses revealed tissue restricted expression of the three genes with both Bestrophin 1 and Bestrophin 2 are abundantly transcribed in colon. Functionally the bestrophines oligomerise to form tetramers and pentamers in order to act as calcium sensitive chloride channels. It has been shown that Bestrophin interacts with beta catalytic subunit of protein phosphatase 2A (PP2Ac). Such protein protein interaction between Bestrophin and PP2Ac and the structural subunit of PP2A, PR65, was confirmed by reciprocal immunoprecipitation. The interaction between PP2Ac and the Bestrophin takes place near the carboxy terminal end of the protein.
