Abstract
The molecular composition of a core conduction element formed by the α- subunit of cloned epithelial Na+ channels (ENaC) was studied in Planar lipid bilayers. Two pairs of in vitro translated proteins were employed in combinatorial experiments: 1) wild-type (WT) and an N-terminally truncated α(ΔN)-rENaC that displays accelerated kinetics (τ(o) = 32 ± 13 ms, τ(o) = 42 ± 11 ms), as compared with the WT channel (τ(c1) = 18 ± 8 ms, τ(c2) = 252 ± 31 ms, and τ(o) = 157 ± 43 ms); and 2) WT and an amiloride binding mutant, α(Δ278-283)-rENaC. The channels that formed in a α(WT):α(AN) mixture fell into two groups: one with τ(o) and τ(c) that corresponded to those exhibited by the α(ΔN)-rENaC alone, and another with a double- exponentially distributed closed time and a single-exponentially distributed open time that corresponded to the α(WT)-rENaC alone. Five channel subtypes with distinct sensitivities to amiloride were found in a 1α(WT):1α(Δ278- 283) protein mixture. Statistical analyses of the distributions of channel phenotypes observed for either set of the WT:mutant combinations suggest a tetrameric organization of α-subunits as a minimal model for the core conduction element in ENaCs.
| Original language | English |
|---|---|
| Pages (from-to) | 2292-2301 |
| Number of pages | 10 |
| Journal | Biophysical Journal |
| Volume | 75 |
| Issue number | 5 |
| Publication status | Published - Nov 1998 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biophysics
Cite this
Subunit stoichiometry of a core conduction element in a cloned epithelial amiloride-sensitive Na+ channel. / Berdiev, Bakhrom K.; Karlson, Katherine H.; Jovov, Biljana; Ripoll, Pierre Jean; Morris, Ryan; Loffing-Cueni, Dominique; Halpin, Patricia; Stanton, Bruce A.; Kleyman, Thomas R.; Ismailov, Iskander I.
In: Biophysical Journal, Vol. 75, No. 5, 11.1998, p. 2292-2301.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Subunit stoichiometry of a core conduction element in a cloned epithelial amiloride-sensitive Na+ channel
AU - Berdiev, Bakhrom K.
AU - Karlson, Katherine H.
AU - Jovov, Biljana
AU - Ripoll, Pierre Jean
AU - Morris, Ryan
AU - Loffing-Cueni, Dominique
AU - Halpin, Patricia
AU - Stanton, Bruce A.
AU - Kleyman, Thomas R.
AU - Ismailov, Iskander I.
PY - 1998/11
Y1 - 1998/11
N2 - The molecular composition of a core conduction element formed by the α- subunit of cloned epithelial Na+ channels (ENaC) was studied in Planar lipid bilayers. Two pairs of in vitro translated proteins were employed in combinatorial experiments: 1) wild-type (WT) and an N-terminally truncated α(ΔN)-rENaC that displays accelerated kinetics (τ(o) = 32 ± 13 ms, τ(o) = 42 ± 11 ms), as compared with the WT channel (τ(c1) = 18 ± 8 ms, τ(c2) = 252 ± 31 ms, and τ(o) = 157 ± 43 ms); and 2) WT and an amiloride binding mutant, α(Δ278-283)-rENaC. The channels that formed in a α(WT):α(AN) mixture fell into two groups: one with τ(o) and τ(c) that corresponded to those exhibited by the α(ΔN)-rENaC alone, and another with a double- exponentially distributed closed time and a single-exponentially distributed open time that corresponded to the α(WT)-rENaC alone. Five channel subtypes with distinct sensitivities to amiloride were found in a 1α(WT):1α(Δ278- 283) protein mixture. Statistical analyses of the distributions of channel phenotypes observed for either set of the WT:mutant combinations suggest a tetrameric organization of α-subunits as a minimal model for the core conduction element in ENaCs.
AB - The molecular composition of a core conduction element formed by the α- subunit of cloned epithelial Na+ channels (ENaC) was studied in Planar lipid bilayers. Two pairs of in vitro translated proteins were employed in combinatorial experiments: 1) wild-type (WT) and an N-terminally truncated α(ΔN)-rENaC that displays accelerated kinetics (τ(o) = 32 ± 13 ms, τ(o) = 42 ± 11 ms), as compared with the WT channel (τ(c1) = 18 ± 8 ms, τ(c2) = 252 ± 31 ms, and τ(o) = 157 ± 43 ms); and 2) WT and an amiloride binding mutant, α(Δ278-283)-rENaC. The channels that formed in a α(WT):α(AN) mixture fell into two groups: one with τ(o) and τ(c) that corresponded to those exhibited by the α(ΔN)-rENaC alone, and another with a double- exponentially distributed closed time and a single-exponentially distributed open time that corresponded to the α(WT)-rENaC alone. Five channel subtypes with distinct sensitivities to amiloride were found in a 1α(WT):1α(Δ278- 283) protein mixture. Statistical analyses of the distributions of channel phenotypes observed for either set of the WT:mutant combinations suggest a tetrameric organization of α-subunits as a minimal model for the core conduction element in ENaCs.
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UR - http://www.scopus.com/inward/citedby.url?scp=0031752505&partnerID=8YFLogxK
M3 - Article
VL - 75
SP - 2292
EP - 2301
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 5
ER -