Table 6.

Substrate selectivities of cytoplasmic membrane channel proteins (excluding porins)

Channel typeNo. of families identifiedFamilies
Nonselective14MscL, CAPs, holins, colicin, ICP, αHL, aerolysin, colicin V, ɛ-toxin, YKT-K1, connexin, innexin, CHL, MscS
Cation selective9ACC, VIC, GIC, RIR-CaC, TRP-CC, ENaC, LIC, NSCC1, NSCC2
Anions6 or 7LIC, ClC, O-ClC, E-ClC, PLM, Tic110, (ABC)
H+2IVC, CybB
Na+2ENaC, VIC
K+2VIC, IRK-C
Ca2+5ACC, VIC, GIC, RIR-CaC, TRP-CC
NH4+1SAT
Small neutral organic molecules1MIP, UT
Organic anions1PLM
Urea2MIP, UT
Water2MIP, UT
Proteins5Holins, Bcl-2, DT, MscL, BTT