FIGURE 7.

A tetrameric model of PC2 channel assembly. The existence of N- and C-terminal dimerization domains would facilitate the assembly of four PC2 monomers into a homotetramer. By contrast, a mutant PC2 monomer lacking the distal C-terminal dimerization domain (such as L703X) would still be capable of forming dimers via the proximal N-terminal domain: these mutant dimers could be functional. The incorporation of one mutant PC2 monomer with 3 normal PC2 monomers would permit the formation of a tetrameric structure but is likely to be non-functional.