The molecular structure of cyclic nucleotide-gated potassium channels (Knuc) is still undefined. Knuc is an important class of K channel since it may participate in the regulation of arterial tone and therefore play an important role in the pathogenesis of hypertension. Based on phylogenetic data, we hypothesized that Knuc should contain the essential features of both Shaker (gene family encodes voltage-gated K channels) K channels and of cyclic nucleotide-gated non-selective cation (Cnuc) channels. A rabbit probe derived from the nucleotide binding domain of cGMP-gated cation channels was isolated. The gene encodes a novel polypeptide (Kcn) that contains the essential characteristics of voltage- gated K channels. Most importantly, unlike any other Shaker K channel protein, Kcn contains a cyclic nucleotide-binding domain. Xenopus oocytes injected with Kcn RNA express a voltage-gated K current that is activated by cGMP. This is to our knowledge the first molecular description of a cGMP-gated K channel. Kcn could, in part, mediated the effects of vasodilatory substances that increase intracellular cGMP. Based on the above findings, we propose to further characterize the Kcn protein in terms of its kinetic properties (Expression in Xenopus oocytes) and tissue distribution (Immunocytochemistry). A cell line that is stably transfected with the Kcn gene will be generated and will be used to examine several aspects of Kcn protein regulation: Is Kcn function regulated by substances (Atrial natriuretic peptide (ANP), Vasopressin (AVP) etc) that increase intracellular cGMP and cAMP in cultured cells? Is the protein phosphorylated in vivo and in vitro? Which kinases best explain the observed effect of hormone (AVP, AV) on channel function? Is gene expression glucocorticoid-responsive? Using site directed mutagenesis, we will also address a limited number of questions regarding structure-function relationships of the cyclic nucleotide binding site and the putative phosphorylation sites.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK048105-01
Application #
2148183
Study Section
General Medicine B Study Section (GMB)
Project Start
1994-04-01
Project End
1997-03-31
Budget Start
1994-04-01
Budget End
1995-03-31
Support Year
1
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Yale University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Desir, Gary V (2009) Regulation of blood pressure and cardiovascular function by renalase. Kidney Int 76:366-70
Li, Guoyong; Xu, Jianchao; Wang, Peili et al. (2008) Catecholamines regulate the activity, secretion, and synthesis of renalase. Circulation 117:1277-82
Desir, Gary V (2008) Renalase deficiency in chronic kidney disease, and its contribution to hypertension and cardiovascular disease. Curr Opin Nephrol Hypertens 17:181-5
Li, Yanyan; Wang, Peili; Xu, Jianchao et al. (2007) Regulation of insulin secretion and GLUT4 trafficking by the calcium sensor synaptotagmin VII. Biochem Biophys Res Commun 362:658-64
Li, Yanyan; Wang, Peili; Xu, Jianchao et al. (2006) Voltage-gated potassium channel Kv1.3 regulates GLUT4 trafficking to the plasma membrane via a Ca2+-dependent mechanism. Am J Physiol Cell Physiol 290:C345-51
Hebert, Steven C; Desir, Gary; Giebisch, Gerhard et al. (2005) Molecular diversity and regulation of renal potassium channels. Physiol Rev 85:319-71
Xu, Jianchao; Li, Guoyong; Wang, Peili et al. (2005) Renalase is a novel, soluble monoamine oxidase that regulates cardiac function and blood pressure. J Clin Invest 115:1275-80
Xu, Jianchao; Wang, Peili; Li, Yanyan et al. (2004) The voltage-gated potassium channel Kv1.3 regulates peripheral insulin sensitivity. Proc Natl Acad Sci U S A 101:3112-7
Tian, Shulan; Liu, Weimin; Wu, Yanling et al. (2002) Regulation of the voltage-gated K+ channel KCNA10 by KCNA4B, a novel beta-subunit. Am J Physiol Renal Physiol 283:F142-9
Segal, Alan S; Hayslett, John P; Desir, Gary V (2002) On the natriuretic effect of verapamil: inhibition of ENaC and transepithelial sodium transport. Am J Physiol Renal Physiol 283:F765-70

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