Kv2.1/Kv9.3, a novel ATP-dependent delayed-rectifier K+ channel in oxygen-sensitive pulmonary artery myocytes.
The molecular structure of oxygen-sensitive delayed-rectifier K+ channels which are involved in hypoxic pulmonary artery (PA) vasoconstriction has yet to be elucidated. To address this problem, we identified the Shab K+ channel Kv2.1 and a novel Shab-like subunit Kv9.3, in rat PA myocytes. Kv9.3 encodes an electrically silent subunit which associates with Kv2.1 and modulates its biophysical properties. The Kv2.1/9.3 heteromultimer, unlike Kv2.1, opens in the voltage range of the resting membrane potential of PA myocytes. Moreover, we demonstrate that the activity of Kv2.1/Kv9.3 is tightly controlled by internal ATP and is reversibly inhibited by hypoxia. In conclusion, we propose that metabolic regulation of the Kv2.1/Kv9.3 heteromultimer may play an important role in hypoxic PA vasoconstriction and in the possible development of PA hypertension.
Pubmed ID: 9362476 RIS Download
Adenosine Triphosphate | Amino Acid Sequence | Anaerobiosis | Animals | Cloning, Molecular | Delayed Rectifier Potassium Channels | Ion Channel Gating | Molecular Sequence Data | Muscle, Smooth, Vascular | Oxygen | Phylogeny | Potassium Channels | Potassium Channels, Voltage-Gated | Protein Binding | Pulmonary Artery | Rats | Rats, Sprague-Dawley | Recombinant Proteins | Sequence Analysis, DNA | Sequence Homology, Amino Acid | Shab Potassium Channels