Many substrates for P-glycoprotein, an ABC transporter that mediates multidrug resistance in
mammalian cells, have been shown to stimulate its ATPase activity in vitro. In the present
study, we used this property as a criterion to search for natural and artificial substrates
and/or allosteric regulators of ABCR, the rod photoreceptor-specific ABC transporter
responsible for Stargardt disease, an early onset macular degeneration. ABCR was
immunoaffinity purified to apparent homogeneity from bovine rod outer segments and …