Abstract
The inactivation of the C1C-0 chloride channel is very temperature sensitive and is greatly facilitated by the binding of a zinc ion (Zn2+) from the extracellular side, leading to a Zn2+-induced current inhibition. To further explore the relation of Zn2+ inhibition and the C1C-0 inactivation, we mutated all 12 cysteine amino acids in the channel and assayed the effect of Zn2+ on these mutants. With this approach, we found that C212 appears to be important for the sensitivity of the Zn2+ inhibition. Upon mutating C212 to serine or alanine, the inactivation of the channel in macroscopic current recordings disappears and the channel does not show detectable inactivation events at the single-channel level. At the same time, the channel's sensitivity to Zn2+ inhibition is also greatly reduced. The other two cysteine mutants, C213G and C480S, as well as a previously identified mutant, S123T, also affect the inactivation of the channel to some degree, but the temperature-dependent inactivation process is still present, likewise the high sensitivity of the Zn2+ inhibition. These results further support the assertion that the inhibition of Zn2+ on C1C-0 is indeed due to an effect on the inactivation of the channel. The absence of inactivation in C212S mutants may provide a better defined system to study the fast gating and the ion permeation of C1C-0.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1-12 |
| Number of pages | 12 |
| Journal | Journal of General Physiology |
| Volume | 114 |
| Issue number | 1 |
| State | Published - Jul 1999 |
| Externally published | Yes |
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Keywords
- C1C-0
- Cysteine mutagenesis
- Slow gating
- Zn inhibition
ASJC Scopus subject areas
- Physiology
Cite this
Elimination of the slow gating of C1C-0 chloride channel by a point mutation. / Lin, Yu Wen; Lin, Chia Wei; Chen, Tsung-Yu.
In: Journal of General Physiology, Vol. 114, No. 1, 07.1999, p. 1-12.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Elimination of the slow gating of C1C-0 chloride channel by a point mutation
AU - Lin, Yu Wen
AU - Lin, Chia Wei
AU - Chen, Tsung-Yu
PY - 1999/7
Y1 - 1999/7
N2 - The inactivation of the C1C-0 chloride channel is very temperature sensitive and is greatly facilitated by the binding of a zinc ion (Zn2+) from the extracellular side, leading to a Zn2+-induced current inhibition. To further explore the relation of Zn2+ inhibition and the C1C-0 inactivation, we mutated all 12 cysteine amino acids in the channel and assayed the effect of Zn2+ on these mutants. With this approach, we found that C212 appears to be important for the sensitivity of the Zn2+ inhibition. Upon mutating C212 to serine or alanine, the inactivation of the channel in macroscopic current recordings disappears and the channel does not show detectable inactivation events at the single-channel level. At the same time, the channel's sensitivity to Zn2+ inhibition is also greatly reduced. The other two cysteine mutants, C213G and C480S, as well as a previously identified mutant, S123T, also affect the inactivation of the channel to some degree, but the temperature-dependent inactivation process is still present, likewise the high sensitivity of the Zn2+ inhibition. These results further support the assertion that the inhibition of Zn2+ on C1C-0 is indeed due to an effect on the inactivation of the channel. The absence of inactivation in C212S mutants may provide a better defined system to study the fast gating and the ion permeation of C1C-0.
AB - The inactivation of the C1C-0 chloride channel is very temperature sensitive and is greatly facilitated by the binding of a zinc ion (Zn2+) from the extracellular side, leading to a Zn2+-induced current inhibition. To further explore the relation of Zn2+ inhibition and the C1C-0 inactivation, we mutated all 12 cysteine amino acids in the channel and assayed the effect of Zn2+ on these mutants. With this approach, we found that C212 appears to be important for the sensitivity of the Zn2+ inhibition. Upon mutating C212 to serine or alanine, the inactivation of the channel in macroscopic current recordings disappears and the channel does not show detectable inactivation events at the single-channel level. At the same time, the channel's sensitivity to Zn2+ inhibition is also greatly reduced. The other two cysteine mutants, C213G and C480S, as well as a previously identified mutant, S123T, also affect the inactivation of the channel to some degree, but the temperature-dependent inactivation process is still present, likewise the high sensitivity of the Zn2+ inhibition. These results further support the assertion that the inhibition of Zn2+ on C1C-0 is indeed due to an effect on the inactivation of the channel. The absence of inactivation in C212S mutants may provide a better defined system to study the fast gating and the ion permeation of C1C-0.
KW - C1C-0
KW - Cysteine mutagenesis
KW - Slow gating
KW - Zn inhibition
UR - http://www.scopus.com/inward/record.url?scp=0033000370&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033000370&partnerID=8YFLogxK
M3 - Article
C2 - 10398688
AN - SCOPUS:0033000370
VL - 114
SP - 1
EP - 12
JO - Journal of General Physiology
JF - Journal of General Physiology
SN - 0022-1295
IS - 1
ER -