Table 4.
Changes in HV1 properties in S2 (134–156) and S2–S3 linker (157–165) mutants versus WT channels
MutantSpeciesExpr. systemI?τactτtailΔVthrΔpH slopeSelectivityOtherReference
Y134A hHV1 HEK wc Yes   3    Ramsey et al., 2010  
H140A hHV1 HEK wc Yes     H+ 9 × Kda Zn2+ Ramsey et al., 2006  
H140A hHV1 Vesicle flux       nc H+ flux Letts, 2014  
H193A hHV1 HEK wc Yes     H+ 39 × Kda Zn2+ Ramsey et al., 2006  
H140A/ H193A hHV1 HEK wc Yes   −12 46 H+ 2,000 × Kda Zn2+ Ramsey et al., 2006  
H140A/ H193A hHV1 COS/HEK wc Yes     H+  Musset et al., 2011  
Y141A hHV1 HEK wc Yes   −27    Ramsey et al., 2010  
S143A hHV1 HEK wc Yes   11 41   Ramsey et al., 2010  
S143A hHV1 Vesicle flux       nc H+ flux Letts, 2014  
D112V/S143D hHV1 COS/HEK wc Yes     Cl–  Morgan et al., 2013  
D112V/I146D hHV1 COS/HEK wc No       Morgan et al., 2013  
D112V/L147D hHV1 COS/HEK wc No       Morgan et al., 2013  
F150A hHV1 Xenopus i-o Yes   −24    Hong et al., 2013  
F150C hHV1 Xenopus i-o Yes   −22    Hong et al., 2013  
F150W hHV1 Xenopus i-o Yes   −55    Hong et al., 2013  
E153A hHV1 HEK wc Yes   −55 42   Ramsey et al., 2010  
E153A CiHV1 [E201A] Xenopus TEVC No       Chamberlin et al., 2014  
E153G CiHV1 [E201G] Xenopus TEVC No       Chamberlin et al., 2014  
E153N hHV1 HEK wc Yes   −1.17 45   Ramsey et al., 2010  
E153A hHV1 Vesicle flux       nc H+ flux Letts, 2014  
E153D hHV1 HEK wc Yes   −23 37   Ramsey et al., 2010  
E153D/D174E hHV1 HEK wc Yes   −102 40   Ramsey et al., 2010  
E153C hHV1 Xenopus i-o Yes   −55    Tombola et al., 2010  
E153C CiHV1 [E201C] Xenopus TEVC Yes   −101    Chamberlin et al., 2014  
E153C/R205C CiHV1 [E201C/R255C] Xenopus TEVC Yes   −43    Chamberlin et al., 2014  
E153C/R208 CiHV1 [E201C/R258C] Xenopus TEVC Yes   37    Chamberlin et al., 2014  
E153C/R211C CiHV1 [E201CR261C] Xenopus TEVC Yes   −60    Chamberlin et al., 2014  
K157A hHV1 HEK wc Yes   1 39   Ramsey et al., 2010  
K157A hHV1 Vesicle flux       nc H+ flux Letts, 2014  
R162A hHV1 HEK wc Yes   13    Ramsey et al., 2010  

That numerical entries are shown does not imply that any given change was significant. Italicized mutant entries from nonhuman species show the hHV1 equivalent. HEK, HEK-293, HEK-293T, tsA, or HM1; COS, COS-7; Xenopus, Xenopus laevis oocyte; wc, whole cell; i-o, inside-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. The ΔVthreshold value is the change in absolute position of the gH–V relationship versus WT. The ΔpH slope is the slope in millivolts of the relationship between Vthreshold (or other parameters reflecting the absolute position of the gH–V relationship) and Vrev or EH (which are not identical; see section Table entries defined).

a

Nominal Kd values are nearly meaningless for Zn2+ inhibition of HV1 because its main effects are slowing activation and shifting the gH–V relationship positively (Cherny and DeCoursey, 1999). As demonstrated in the Appendix of DeCoursey et al. (2001a), the apparent Kd derived from the ratio IH(Zn2+)/IH can vary more than three orders of magnitude depending on the test potential selected. If all measurements are done the same way, relative Kd values have meaning.

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