Figure 2.

PDZ-based protein–protein interaction in bicarbonate-transporting epithelia. Many membrane receptors and transporters participating in the bicarbonate homeostasis in epithelial cells have a PDZ-binding motif (-X-T/S-X-hydrophobic amino acid) on their carboxyl terminus. The carboxy-terminal sequences are based on the human clones. Excluding purinergic receptors, most of the proteins are associated with cAMP-dependent processes. AC, Adenylyl cyclase; AKAP, cAMP-dependent protein kinase-anchoring protein; P2, purinergic receptor; RII, regulatory subunit of protein kinase A type II. (Other abbreviations are the same as described in the text.)