TY - JOUR T1 - BESTROPHIN1 mutations cause defective chloride conductance in patient stem cell-derived RPE. JF - Hum Mol Genet Y1 - 2016 A1 - Moshfegh, Yasmin A1 - Velez, Gabriel A1 - Li, Yao A1 - Bassuk, Alexander G A1 - Mahajan, Vinit B A1 - Tsang, Stephen H KW - Bestrophins KW - Calcium Signaling KW - Chloride Channels KW - Chlorides KW - Eye Proteins KW - Humans KW - Induced Pluripotent Stem Cells KW - Mutation KW - Retinal Pigment Epithelium KW - Vitelliform Macular Dystrophy AB -

Bestrophin1 (BEST1) is expressed in human retinal pigment epithelium (RPE) and mutations in the BEST1 gene commonly cause retinal dysfunction and macular degeneration. BEST1 is presumed to assemble into a calcium-activated chloride channel and be involved in chloride transport but there is no direct evidence in live human RPE cells to support this idea. To test whether BEST1 functions as a chloride channel in living tissue, BEST1-mutant RPE (R218H, L234P, A243T) were generated from patient-derived induced pluripotent stem cells and compared with wild-type RPE in a retinal environment, using a biosensor that visualizes calcium-induced chloride ion flux in the cell. Calcium stimulation elicited chloride ion export in normal RPE but not in RPE derived from three patients with BEST1 mutations. These data, along with three-dimensional modeling, provide evidence that BEST1 assembles into a key calcium-sensing chloride channel in human RPE.

VL - 25 IS - 13 U1 - http://www.ncbi.nlm.nih.gov/pubmed/27193166?dopt=Abstract ER -