Limited proteolysis of gap junction protein is intrinsic in mammalian lens fiber-cell plasma membranes.
We demonstrate that the limited proteolysis of the lens fiber-cell gap junction protein, MP26, is intrinsic in mammalian lens fiber plasma membranes. Incubations of isolated intact bovine lens fiber plasma membranes in buffer alone did not elicit proteolysis of MP26. Incubations in the buffer with detergent, however, resulted in the limited proteolysis of MP26 which was totally inhibited by calcium chelators, thiol-alkylating agents, and protease inhibitors. As the limited proteolysis required the presence of detergent, it must depend on an enzymatic activity intrinsic in the lens fiber plasma membranes or in MP26 itself.
D000818:Animals; D020346:Aquaporins; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000494:pharmacology; D003902:Detergents / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005136:Eye Proteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007908:Lens, Crystalline / Q000187:drug effects / Q000201:enzymology*; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013696:Temperature
D020346:Aquaporins; D002593:Cetrimonium Compounds; D003902:Detergents; D005136:Eye Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011480:Protease Inhibitors; D013439:Sulfhydryl Reagents; C030328:aquaporin 0; D004533:Egtazic Acid; D010447:Peptide Hydrolases; D000077286:Cetrimonium