Lens sodium channels are inactivated by anti-MIP26 antibodies

Sodium-specific channels can be functionally identified in phosphatidylcholine liposomes incorporating detergent-solubilized membrane proteins from pig lens epithelium and outer cortex. The transport of sodium is saturable, specific and protease-sensitive. MIP26 was identified in the solubilized membrane fraction and in the liposomes by means of Western blot analysis. Pre-treatment of liposomes with anti-MIP26 antiserum abolished the transport of sodium. These data indicate that MIP26 is associated to a sodium selective transport activity.