Contributions of the C-terminal domain to gating properties of inward rectifier potassium channels.
Two inward rectifier potassium channels, the G protein-dependent GIRK1 and the G protein-independent BIR10, display large differences in rectification and macroscopic kinetics. A chimeric channel was constructed in which the putative intracellular carboxy-terminal domain of the G protein-dependent channel replaced the corresponding domain of the G protein-independent channel. The chimeric channel conducted potassium ions without the requirement of activated G proteins, yet displayed activation and deactivation kinetics and rectification properties similar to those of the G protein-dependent channel. The results demonstrate that structural elements in the C-terminus can independently control gating but not G protein signal transduction. The voltage dependence, time course, and kinetics of gating suggest a mechanism in which the pore may be occluded by reversible interactions with charged residues in the C-terminus.
Pessia
M
M
Vollum Institute, Oregon Health Sciences University, Portland 97201, USA.
Bond
C T
CT
Kavanaugh
M P
MP
Adelman
J P
JP
D000595:Amino Acid Sequence; D004553:Electric Conductivity; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D019204:GTP-Binding Proteins / Q000502:physiology; D015640:Ion Channel Gating / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000737:chemistry* / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying; D011993:Recombinant Fusion Proteins / Q000502:physiology; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D000098854:Kcnj10 Channel
D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D000098854:Kcnj10 Channel; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011993:Recombinant Fusion Proteins; D019204:GTP-Binding Proteins