Table 7. Changes in H V 1 properties in... | Rockefeller University Press

Table 7.

Changes in H_V1 properties in C-terminal (219–273) mutants versus WT channels

Mutant	Species	Expr. system	I?	τ_act	τ_tail	ΔV_thr	ΔpH slope	Selectivity	Other	Reference
S219P	hH_V1	COS/HEK wc	Yes					H⁺		Musset et al., 2011
C249S	hH_V1								Loss of dimer formation	Li et al., 2015
ΔC (T222stop)	hH_V1	HEK wc	Yes			1	28			Ramsey et al., 2010
ΔC (T222stop)	hH_V1		Yes	0.15					Weaker Zn²⁺ effects	Musset et al., 2010b
ΔC	mH_V1 (V216stop)	HEK wc	Yes	0.34		nc	nc		Loss of dimer formation	Koch et al., 2008
ΔC	mH_V1 (V216stop)	HEK wc	Yes	0.15	0.16					Okuda et al., 2016
ΔC	CiH_V1 (D275stop)	Xenopus TEVC	Yes	0.14	0.075					Okuda et al., 2016
V220G/ K221G/T222G	mH_V1 V216G/K217G/T218G	HEK wc							Loss of cooperative gating	Fujiwara et al., 2012

Mutant	Species	Expr. system	I?	τ_act	τ_tail	ΔV_thr	ΔpH slope	Selectivity	Other	Reference
S219P	hH_V1	COS/HEK wc	Yes					H⁺		Musset et al., 2011
C249S	hH_V1								Loss of dimer formation	Li et al., 2015
ΔC (T222stop)	hH_V1	HEK wc	Yes			1	28			Ramsey et al., 2010
ΔC (T222stop)	hH_V1		Yes	0.15					Weaker Zn²⁺ effects	Musset et al., 2010b
ΔC	mH_V1 (V216stop)	HEK wc	Yes	0.34		nc	nc		Loss of dimer formation	Koch et al., 2008
ΔC	mH_V1 (V216stop)	HEK wc	Yes	0.15	0.16					Okuda et al., 2016
ΔC	CiH_V1 (D275stop)	Xenopus TEVC	Yes	0.14	0.075					Okuda et al., 2016
V220G/ K221G/T222G	mH_V1 V216G/K217G/T218G	HEK wc							Loss of cooperative gating	Fujiwara et al., 2012

That numerical entries are shown does not imply that any given change was significant. HEK, HEK-293, HEK-293T, tsA, or HM1; COS, COS-7; Xenopus, Xenopus laevis oocyte; wc, whole cell; i-o, inside-out patch configuration; o-o, outside-out patch configuration; TEVC, two-electrode voltage clamp. Blank entries indicate that the parameter was not examined. nc, measured, but no change. Parameters are given relative to WT in each study. For I?, yes means currents are detectable. Time constants are ratios of mutant/WT. The ΔV_threshold value is the change in absolute position of the g_H–V relationship versus WT. The ΔpH slope is the slope in millivolts of the relationship between V_threshold (or other parameters reflecting the absolute position of the g_H–V relationship) and V_rev or E_H (which are not identical; see section Table entries defined). When C-terminal truncations are indicated as XNNNstop, this means STOP replaces X at position NNN; hence, position NNN and all subsequent residues are truncated, and the last position remaining is NNN-1. The mouse N-terminal deletions were done by replacing P78M to initiate translation at that position. Note that a large number of mutations to the linker between S4 and the C terminus have been studied (Fujiwara et al., 2012, 2014), but their results are beyond the scope of this table and thus are not included.

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