ATP-sensitive potassium channels exhibit variance in the number of open channels below the limit predicted for identical and independent gating.
PLoS One
; 7(5): e37399, 2012.
Article
in En
| MEDLINE
| ID: mdl-22666353
ABSTRACT
In small cells containing small numbers of ion channels, noise due to stochastic channel opening and closing can introduce a substantial level of variability into the cell's membrane potential. Negatively cooperative interactions that couple a channel's gating conformational change to the conformation of its neighbor(s) provide a potential mechanism for mitigating this variability, but such interactions have not previously been directly observed. Here we show that heterologously expressed ATP-sensitive potassium channels generate noise (i.e., variance in the number of open channels) below the level possible for identical and independent channels. Kinetic analysis with single-molecule resolution supports the interpretation that interchannel negative cooperativity (specifically, the presence of an open channel making a closed channel less likely to open) contributes to the decrease in noise. Functional coupling between channels may be important in modulating stochastic fluctuations in cellular signaling pathways.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ion Channel Gating
/
KATP Channels
Type of study:
Diagnostic_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Humans
Language:
En
Journal:
PLoS One
Journal subject:
CIENCIA
/
MEDICINA
Year:
2012
Type:
Article
Affiliation country:
United States