Aquaporin CHIP: the archetypal molecular water channel

Human red blood cells, CHIP28, yields CHIP, a 28-kDa channel-forming integral membrane protein, which is identified to determine the molecular properties of membrane water channels. Osmosis, seen in CHIP, causes water-selective pore movement. Enhancement in osmotic water permeability is seen in Xenopus oocytes due to CHIP expression. Transmembrane movement of ions or other minute molecules is not permitted by CHIP. Permeability of unit water is determined by the recreation of distilled CHIP into proteoliposomes.