A novel method of ligand peptidomics to identify peptide ligands binding to AQP2-expressing plasma membranes and intracellular vesicles of rat kidney

摘要

Aquaporin-2 (AQP2), the vaso-pressin-regulated water channel in collecting duct principal cells, plays a key role in the regulation of body water balance. We aimed to isolate high-affinity peptide ligands that bind to immunoisolated AQP2-expressing plasma membrane (PM) or intracellular vesicle (ICV) preparations from rat kidney by the in vitro phage display technique. Immunoblotting revealed that AQP2 was exclusively expressed in the immunoisolated AQP2 membrane fractions (PM and ICV), compared with the nonimmunoisolated or preimmune IgG pulldown rat kidney samples.