Table 2: Functional properties of mutant nAChRs linked to sleep-related epilepsy.

MutantCloneCell typeγ Potentiation by Sensitivity to ACh References
HomoHet HomoHetHomo Het

α4-S248FHumanXenopus nd ndndndndnd nond[248, 250, 251]
HumanXenopus ndndnd nond[249]
Human Xenopus ndno ndnd↑↑[252, 253]
RatXenopus ndnd nond[254257]
α4-S252LHuman
Xenopus nd

no
no
nd
nd
↑↑
↑↑

[252, 253]
RatXenopus ndnondndndnd(↑)nd[254]
RatXenopus ndndnd ndnond[256, 257]
α4-776ins3HumanXenopus ndnonond↑↑↑↑ [225, 250, 252, 253]
RatXenopus (↑)nondnond no [254, 256, 257]
α4-T265IHumanXenopus nd()()ndndnd no [228, 253]
β2-V287LHuman HEK no*nono * no*(↑)nd ↑↑ [164]
RatXenopus ()ndndndnd(↑)nd no[256, 257]
β2-V287MHumanXenopus ndnondndnd ↑↑↑↑ no [165, 252]
HEKno[231]
RatXenopus ndndndnd(↑)nd no [256, 257]
β2-I312MHumanXenopus ndnd↑↑nd nd↑↑ ↑↑ no [230]
β2-L301VHumanXenopus nd↑↑↑↑ nd nd no[231]
HEK/GH4-C1no no
β2-V308AHumanXenopus nd nd nd no[231]
HEK/GH4-C1no no
α2-I279NHuman HEK (with β4)no*nonond nd↑↑ no[21, 245]
Xenopus (with β2)ndndndnd nd↑↑ no[246]

Legend: γ: single-channel conductance; homo: homozygous condition; hetero: heterozygous condition; : current measured in the presence of saturating agonist concentrations; nd: not determined; : permeability to Ca2+; : monoexponential time constant of desensitization; ↑: increase; (↑): small increase; ↑↑: strong increase; : decrease; (): small decrease; : strong decrease. *A. Becchetti and C. Di Resta, unpublished results.