Abstract
1. The effect of protein kinase activators on cloned inward rectifier channels expressed in Xenopus oocytes was examined using a two-electrode voltage clamp. PKA activators caused no change in KIR1.1, KIR2.1, or KIR2.3 current. The PKC activators phorbol 12-myristate 14-acetate (PMA) and phorbol 12, 13-dibutyrate (PDBu) inhibited KIR2.3 currents, but not KIR2.1 or KIR1.1 current. This inhibition was blocked by staurosporine. An inactive phorbol ester, 4 alpha-phorbol 12, 13-didecanoate (4 alpha-PDD), had no effect on KIR2.3. 2. Upon changing solution from 2 to 98 microM K+, KIR2.3 but not KIR1.1 or KIR2.1 currents typically 'ran down' over 5 min to 60-80% of maximum amplitude. Rundown occurred even if PMA was applied before changing to high [K+] solution, indicating that rundown was independent of PKC activity. Rundown was evoked by substituting NMG+ for Na+, showing that it results from low [Na+] and not from high [K+]. 3. These results suggest that KIR2.3, but not KIR1.1 or KIR2.1, is subject to regulation, both by PKC activation and as a consequence of low [Na+]o. The difference in secondary regulation may account for specific responses to PKC stimulation of tissues expressing otherwise nearly identical KIR channels.
Full text
PDF![681](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/1dcb813eb30b/jphysiol00394-0087.png)
![682](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/cded3a6302b2/jphysiol00394-0088.png)
![683](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/26ad9578e9c1/jphysiol00394-0089.png)
![684](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/5301ee1cbccc/jphysiol00394-0090.png)
![685](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/000758f3bf15/jphysiol00394-0091.png)
![686](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/402be7c2ed6d/jphysiol00394-0092.png)
![687](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/f02a82645220/jphysiol00394-0093.png)
![688](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f44d/1160774/cfb01817305f/jphysiol00394-0094.png)
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Armstrong S., Downey J. M., Ganote C. E. Preconditioning of isolated rabbit cardiomyocytes: induction by metabolic stress and blockade by the adenosine antagonist SPT and calphostin C, a protein kinase C inhibitor. Cardiovasc Res. 1994 Jan;28(1):72–77. doi: 10.1093/cvr/28.1.72. [DOI] [PubMed] [Google Scholar]
- Billman G. E. Role of ATP sensitive potassium channel in extracellular potassium accumulation and cardiac arrhythmias during myocardial ischaemia. Cardiovasc Res. 1994 Jun;28(6):762–769. doi: 10.1093/cvr/28.6.762. [DOI] [PubMed] [Google Scholar]
- Burckhardt B. C., Kroll B., Frömter E. Proton transport mechanism in the cell membrane of Xenopus laevis oocytes. Pflugers Arch. 1992 Jan;420(1):78–82. doi: 10.1007/BF00378644. [DOI] [PubMed] [Google Scholar]
- Cartaud A., Boyer J., Ozon R. Calcium sequestering activities of reticulum vesicles from Xenopus laevis oocytes. Exp Cell Res. 1984 Dec;155(2):565–574. doi: 10.1016/0014-4827(84)90216-7. [DOI] [PubMed] [Google Scholar]
- Doupnik C. A., Davidson N., Lester H. A. The inward rectifier potassium channel family. Curr Opin Neurobiol. 1995 Jun;5(3):268–277. doi: 10.1016/0959-4388(95)80038-7. [DOI] [PubMed] [Google Scholar]
- Fakler B., Brändle U., Glowatzki E., Zenner H. P., Ruppersberg J. P. Kir2.1 inward rectifier K+ channels are regulated independently by protein kinases and ATP hydrolysis. Neuron. 1994 Dec;13(6):1413–1420. doi: 10.1016/0896-6273(94)90426-x. [DOI] [PubMed] [Google Scholar]
- Ficker E., Taglialatela M., Wible B. A., Henley C. M., Brown A. M. Spermine and spermidine as gating molecules for inward rectifier K+ channels. Science. 1994 Nov 11;266(5187):1068–1072. doi: 10.1126/science.7973666. [DOI] [PubMed] [Google Scholar]
- Hagiwara S., Miyazaki S., Rosenthal N. P. Potassium current and the effect of cesium on this current during anomalous rectification of the egg cell membrane of a starfish. J Gen Physiol. 1976 Jun;67(6):621–638. doi: 10.1085/jgp.67.6.621. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ho K., Nichols C. G., Lederer W. J., Lytton J., Vassilev P. M., Kanazirska M. V., Hebert S. C. Cloning and expression of an inwardly rectifying ATP-regulated potassium channel. Nature. 1993 Mar 4;362(6415):31–38. doi: 10.1038/362031a0. [DOI] [PubMed] [Google Scholar]
- Kubo Y., Baldwin T. J., Jan Y. N., Jan L. Y. Primary structure and functional expression of a mouse inward rectifier potassium channel. Nature. 1993 Mar 11;362(6416):127–133. doi: 10.1038/362127a0. [DOI] [PubMed] [Google Scholar]
- Kubo Y., Reuveny E., Slesinger P. A., Jan Y. N., Jan L. Y. Primary structure and functional expression of a rat G-protein-coupled muscarinic potassium channel. Nature. 1993 Aug 26;364(6440):802–806. doi: 10.1038/364802a0. [DOI] [PubMed] [Google Scholar]
- Kunkel T. A. Rapid and efficient site-specific mutagenesis without phenotypic selection. Proc Natl Acad Sci U S A. 1985 Jan;82(2):488–492. doi: 10.1073/pnas.82.2.488. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lopatin A. N., Makhina E. N., Nichols C. G. Potassium channel block by cytoplasmic polyamines as the mechanism of intrinsic rectification. Nature. 1994 Nov 24;372(6504):366–369. doi: 10.1038/372366a0. [DOI] [PubMed] [Google Scholar]
- Makhina E. N., Kelly A. J., Lopatin A. N., Mercer R. W., Nichols C. G. Cloning and expression of a novel human brain inward rectifier potassium channel. J Biol Chem. 1994 Aug 12;269(32):20468–20474. [PubMed] [Google Scholar]
- Matsuda H., Saigusa A., Irisawa H. Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg2+. Nature. 1987 Jan 8;325(7000):156–159. doi: 10.1038/325156a0. [DOI] [PubMed] [Google Scholar]
- Miyake R., Tanaka Y., Tsuda T., Yamanishi J., Kikkawa U., Nishizuka Y. Membrane phospholipid turnover in signal transduction; protein kinase C and mechanism of action of tumor promoters. Princess Takamatsu Symp. 1983;14:167–176. [PubMed] [Google Scholar]
- Périer F., Radeke C. M., Vandenberg C. A. Primary structure and characterization of a small-conductance inwardly rectifying potassium channel from human hippocampus. Proc Natl Acad Sci U S A. 1994 Jun 21;91(13):6240–6244. doi: 10.1073/pnas.91.13.6240. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Speechly-Dick M. E., Mocanu M. M., Yellon D. M. Protein kinase C. Its role in ischemic preconditioning in the rat. Circ Res. 1994 Sep;75(3):586–590. doi: 10.1161/01.res.75.3.586. [DOI] [PubMed] [Google Scholar]
- Tabcharani J. A., Boucher A., Eng J. W., Hanrahan J. W. Regulation of an inwardly rectifying K channel in the T84 epithelial cell line by calcium, nucleotides and kinases. J Membr Biol. 1994 Nov;142(2):255–266. doi: 10.1007/BF00234947. [DOI] [PubMed] [Google Scholar]
- Takano K., Stanfield P. R., Nakajima S., Nakajima Y. Protein kinase C-mediated inhibition of an inward rectifier potassium channel by substance P in nucleus basalis neurons. Neuron. 1995 May;14(5):999–1008. doi: 10.1016/0896-6273(95)90338-0. [DOI] [PubMed] [Google Scholar]
- Tamaoki T., Nomoto H., Takahashi I., Kato Y., Morimoto M., Tomita F. Staurosporine, a potent inhibitor of phospholipid/Ca++dependent protein kinase. Biochem Biophys Res Commun. 1986 Mar 13;135(2):397–402. doi: 10.1016/0006-291x(86)90008-2. [DOI] [PubMed] [Google Scholar]
- Vandenberg C. A. Inward rectification of a potassium channel in cardiac ventricular cells depends on internal magnesium ions. Proc Natl Acad Sci U S A. 1987 Apr;84(8):2560–2564. doi: 10.1073/pnas.84.8.2560. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wu T., Wang H. L. Protein kinase C mediates neurotensin inhibition of inwardly rectifying potassium currents in rat substantia nigra dopaminergic neurons. Neurosci Lett. 1995 Jan 23;184(2):121–124. doi: 10.1016/0304-3940(94)11185-l. [DOI] [PubMed] [Google Scholar]