SLO-2, a K+ channel with an unusual Cl- dependence.
The gating of different potassium channels depends on many diverse factors. We now report a unique example of a K+ channel with a Cl - dependence. The slo-2 gene was cloned from Caenorhabditis elegans and is widely expressed in both neurons and muscles; it was highly abundant, as suggested by its high representation in the C. elegans EST database. SLO-2, like its paralogue, SLO-1, was also dependent on Ca 2+. We show by site-directed mutagenesis that its requirements for both Cl- and Ca2+ are synergistic and associated with the same functional domain. SLO-2's dependence on Cl - implies that intracellular Cl- homeostasis may be important in regulating cellular excitability through this unusual K+ channel.
Yuan
A
A
Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 South Euclid, Saint Louis, Missouri 63110, USA.
Dourado
M
M
Butler
A
A
Walton
N
N
Wei
A
A
Salkoff
L
L
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins; D002118:Calcium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology / Q000502:physiology*; D017124:Conserved Sequence; D049452:Green Fluorescent Proteins; D015801:Helminth Proteins / Q000502:physiology; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008164:Luminescent Proteins / Q000235:genetics; D008322:Mammals; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009132:Muscles / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D024681:Potassium Channels, Calcium-Activated; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D029742:Caenorhabditis elegans Proteins; D002712:Chlorides; D015801:Helminth Proteins; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008164:Luminescent Proteins; D026901:Membrane Transport Proteins; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; C402625:SLO-2 protein, C elegans; D049452:Green Fluorescent Proteins; D002118:Calcium