Channels and transporters in the ClC family are homodimeric; however, the aqueous pores for anion diffusion in the channels and the ion-coupling chambers that coordinate Cl− and H+ antiport in the transporters are contained wholly within each subunit of the homodimer. Here mutations in a Cl−/H+ exchanger were made that destabilized the dimer interface; the resulting mutant channel is monomeric, yet it is functionally nearly identical to the wild-type channel. This means that cross-subunit interaction is not required for Cl−/H+ exchange in ClC transporters, which raises the question: why is the wild-type transporter a homodimer?
- Janice L. Robertson
- Ludmila Kolmakova-Partensky
- Christopher Miller
