title: Snowflake vitreoretinal degeneration (SVD) mutation R162W provides new insights into Kir7.1 ion channel structure and function.
abstract: Snowflake Vitreoretinal Degeneration (SVD) is associated with the R162W mutation of the Kir7.1 inwardly-rectifying potassium channel. Kir7.1 is found at the apical membrane of Retinal Pigment Epithelial (RPE) cells, adjacent to the photoreceptor neurons. The SVD phenotype ranges from RPE degeneration to an abnormal b-wave to a liquid vitreous. We sought to determine how this mutation alters the structure and function of the human Kir7.1 channel. In this study, we expressed a Kir7.1 construct with the R162W mutation in CHO cells to evaluate function of the ion channel. Compared to the wild-type protein, the mutant protein exhibited a non-functional Kir channel that resulted in depolarization of the resting membrane potential. Upon co-expression with wild-type Kir7.1, R162W mutant showed a reduction of IKir7.1 and positive shift in '0' current potential. Homology modeling based on the structure of a bacterial Kir channel protein suggested that the effect of R162W mutation is a result of loss of hydrogen bonding by the regulatory lipid binding domain of the cytoplasmic structure.
authors: Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, United States of America ; Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States of America ; McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America.
authors: Bikash R
authors: BR
authors: Pattnaik
authors: Sara
authors: S
authors: Tokarz
authors: Matti P
authors: MP
authors: Asuma
authors: Tyler
authors: T
authors: Schroeder
authors: Anil
authors: A
authors: Sharma
authors: Julie C
authors: JC
authors: Mitchell
authors: Albert O
authors: AO
authors: Edwards
authors: De-Ann M
authors: DA
authors: Pillers
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D008253:Macaca mulatta; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D024661:Potassium Channels, Inwardly Rectifying / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D012160:Retina / Q000187:drug effects / Q000378:metabolism; D012162:Retinal Degeneration / Q000235:genetics*; D012413:Rubidium / Q000494:pharmacology; D040681:Structural Homology, Protein; D014162:Transfection
chemical_list: C489477:Kir7.1 channel; D050505:Mutant Proteins; D024661:Potassium Channels, Inwardly Rectifying; D012413:Rubidium
references: J Am Soc Nephrol. 2000 Nov;11(11):1987-1994
references: 11053473
references: Am J Hum Genet. 2008 Jan;82(1):174-80
references: 18179896
references: Biochemistry. 2009 Nov 24;48(46):10926-33
references: 19839652
references: Physiol Rev. 2010 Jan;90(1):291-366
references: 20086079
references: Exp Eye Res. 2008 Jan;86(1):81-91
references: 18035352
references: Cell. 2010 Jun 11;141(6):1018-29
references: 20564790
references: Pflugers Arch. 2007 Oct;455(1):83-95
references: 17520276
references: Neuroscience. 2004;129(4):1045-56
references: 15561419
references: J Physiol. 2001 Mar 1;531(Pt 2):329-46
references: 11230507
references: Am J Clin Pathol. 2012 Jul;138(1):85-9
references: 22706862
references: Nature. 2011 Aug 28;477(7365):495-8
references: 21874019
references: Cell Biol Int. 2006 Mar;30(3):270-7
references: 16406822
references: Biophys J. 2011 May 4;100(9):2121-30
references: 21539779
references: PLoS One. 2008 Jul 30;3(7):e2839
references: 18665233
references: Invest Ophthalmol Vis Sci. 2003 Jul;44(7):3178-85
references: 12824269
references: Genomics. 1998 Dec 15;54(3):560-3
references: 9878260
references: FASEB J. 2010 May;24(5):1552-71
references: 20056717
references: Am J Physiol. 1998 Nov;275(5):C1372-83
references: 9814987
references: Eye (Lond). 2008 Oct;22(10):1233-42
references: 18309337
references: Am J Physiol Cell Physiol. 2013 Mar 1;304(5):C440-9
references: 23255580
references: J Neurosci. 1998 Nov 1;18(21):8625-36
references: 9786970
references: Methods Mol Biol. 2008;426:145-59
references: 18542861
references: Am J Hum Genet. 2011 Jul 15;89(1):183-90
references: 21763485
references: J Physiol. 2010 Jun 15;588(Pt 12):2205-18
references: 20403973
references: Annu Rev Biophys. 2008;37:175-95
references: 18573078
references: J Physiol. 2001 Feb 15;531(Pt 1):27-36
references: 11179389
references: J Cell Sci. 2005 May 1;118(Pt 9):1935-43
references: 15827083
references: Am J Physiol. 1995 May;268(5 Pt 1):C1164-72
references: 7762609
references: Prog Retin Eye Res. 2000 Jul;19(4):421-57
references: 10785617
references: Am J Physiol Cell Physiol. 2009 Oct;297(4):C1001-11
references: 19641096
references: Neuron. 1998 May;20(5):995-1005
references: 9620703
references: J Physiol. 2008 Apr 1;586(7):1833-48
references: 18276733
references: PLoS One. 2010 Mar 09;5(5):e9341
references: 20479888
references: J Biol Chem. 2003 Jun 13;278(24):21459-66
references: 12670959
references: Kidney Int. 2001 Jun;59(6):2197-205
references: 11380822
references: Ophthalmologe. 2009 Apr;106(4):299-304
references: 19343352
references: Channels (Austin). 2010 May-Jun;4(3):203-14
references: 20458182
references: Biochem J. 1999 Sep 1;342 ( Pt 2):329-36
references: 10455019
references: Exp Eye Res. 2008 Sep;87(3):176-83
references: 18653180
references: J Pharmacol Toxicol Methods. 2005 May-Jun;51(3):187-200
references: 15862464
references: Physiol Rev. 2005 Jul;85(3):845-81
references: 15987797
references: Invest Ophthalmol Vis Sci. 1996 May;37(6):1125-39
references: 8631627
references: Prog Retin Eye Res. 2007 May;26(3):263-301
references: 17258931
references: Mol Genet Metab. 2012 Jan;105(1):64-72
references: 22079268
references: J Pharmacol Toxicol Methods. 2005 May-Jun;51(3):177-85
references: 15862463
references: Annu Rev Biophys Biomol Struct. 2002;31:151-75
references: 11988466
references: Ophthalmology. 2003 Dec;110(12):2418-26
references: 14644728
references: J Physiol. 2007 Aug 1;582(Pt 3):953-65
references: 17495041