Limited proteolysis of MP26 in lens fiber plasma membranes of the U18666A-induced cataract in rats.

Most of the animals treated with U18666A every other day beginning at one-day of age developed permanent nuclear cataracts by 3-4 weeks of age. Lens fiber plasma membranes were isolated from cortical and nuclear areas of untreated controls, treated but clear, and treated cataractous lenses, and analyzed by SDS-PAGE. MP26 was the major intrinsic polypeptide in the plasma membranes of both cortical and nuclear fibers of control lenses. MP26 was largely replaced by MP23-24 in the plasma membranes of nuclear fibers of treated but clear lenses, and in the membranes of both cortical and nuclear fibers of cataractous lenses.