title: Opposing effects of podocin on the gating of podocyte TRPC6 channels evoked by membrane stretch or diacylglycerol.
abstract: Gain-of-function mutations in the transient receptor potential (TRP) cation channel subfamily C member 6 (TRPC6) gene and mutations in the NPHS2 gene encoding podocin result in nephrotic syndromes. The purpose of this study was to determine the functional significance of biochemical interactions between these proteins. We observed that gating of TRPC6 channels in podocytes is markedly mechanosensitive and can be activated by hyposmotic stretch or indentation of the plasma membrane. Stretch activation of cationic currents was blocked by small interfering RNA knockdown of TRPC6, as well as by SKF-96365 or micromolar La(3+). Stretch activation of podocyte TRPC6 persisted in the presence of inhibitors of phospholipase C (U-73122) and phospholipase A2 (ONO-RS-082). Robust stretch responses also persisted when recording electrodes contained guanosine 5'-O-(2-thiodiphosphate) at concentrations that completely suppressed responses to ANG II. Stretch responses were enhanced by cytochalasin D but were abolished by the peptide GsMTx4, suggesting that forces are transmitted to the channels through the plasma membrane. Podocin and TRPC6 interact at their respective COOH termini. Knockdown of podocin markedly increased stretch-evoked activation of TRPC6 but nearly abolished TRPC6 activation evoked by a diacylglycerol analog. These data suggest that podocin acts as a switch to determine the preferred mode of TRPC6 activation. They also suggest that podocin deficiencies will result in Ca(2+) overload in foot processes, as with gain-of-function mutations in the TRPC6 gene. Finally, they suggest that mechanical activation of TRP family channels and the preferred mode of TRP channel activation may depend on whether members of the stomatin/prohibitin family of hairpin loop proteins are present.
authors: Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA.
authors: Marc
authors: M
authors: Anderson
authors: Eun Young
authors: EY
authors: Kim
authors: Henning
authors: H
authors: Hagmann
authors: Thomas
authors: T
authors: Benzing
authors: Stuart E
authors: SE
authors: Dryer
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002723:Chlorobenzoates / Q000494:pharmacology; D002934:Cinnamates / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D015640:Ion Channel Gating; D007678:Kidney Glomerulus / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D009404:Nephrotic Syndrome; D010455:Peptides / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D064801:Phospholipase A2 Inhibitors; D050199:Podocytes / Q000378:metabolism*; D011760:Pyrrolidinones / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering; D051381:Rats; D013111:Spider Venoms / Q000494:pharmacology; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D000074287:TRPC6 Cation Channel; D013873:Thionucleotides / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors; D062367:ortho-Aminobenzoates / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D002723:Chlorobenzoates; D002934:Cinnamates; D004075:Diglycerides; D004963:Estrenes; D007093:Imidazoles; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; C411249:MTx4 protein, Grammostola spatulata; D008565:Membrane Proteins; C407223:NPHS2 protein; D010455:Peptides; D010726:Phosphodiesterase Inhibitors; D064801:Phospholipase A2 Inhibitors; D011760:Pyrrolidinones; D034741:RNA, Small Interfering; D013111:Spider Venoms; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; D013873:Thionucleotides; C492146:Trpc6 protein, mouse; D062367:ortho-Aminobenzoates; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D006153:Guanosine Diphosphate; D015638:Cytochalasin D; C023427:guanosine 5'-O-(2-thiodiphosphate); C060048:2-(4-amylcinnamoyl)amino-4-chlorobenzoic acid; D010738:Type C Phospholipases; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole
keywords: TRPC6; glomerular filtration; mechanosensitive; podocyte; slit diaphragm
references: J Clin Invest. 1971 Aug;50(8):1776-80
references: 5097578
references: Am J Physiol Renal Physiol. 2008 Oct;295(4):F959-70
references: 18684887
references: Nature. 1981 Oct 22;293(5834):646-7
references: 7290198
references: Circ Res. 2002 Feb 22;90(3):248-50
references: 11861411
references: Kidney Int. 1994 Feb;45(2):369-76
references: 8164421
references: J Am Soc Nephrol. 2010 Nov;21(11):1835-41
references: 20576805
references: Nature. 2007 Jan 11;445(7124):206-9
references: 17167420
references: Pflugers Arch. 2008 Mar;455(6):1097-103
references: 17957383
references: J Clin Invest. 2001 Dec;108(11):1621-9
references: 11733557
references: J Physiol. 2006 Apr 15;572(Pt 2):359-77
references: 16439426
references: J Am Soc Nephrol. 2003 Jan;14(1):46-56
references: 12506137
references: Pflugers Arch. 2010 Aug;460(3):571-81
references: 20490539
references: Kidney Int. 1981 Aug;20(2):188-97
references: 7289403
references: Am J Pathol. 2002 Jan;160(1):131-9
references: 11786407
references: Am J Physiol Renal Physiol. 2007 Dec;293(6):F1787-98
references: 17715264
references: Physiol Rev. 1994 Jul;74(3):637-81
references: 8036249
references: J Biol Chem. 2004 Dec 17;279(51):53886-91
references: 15471860
references: Kidney Int. 2009 Apr;75(7):669-71
references: 19282856
references: Am J Pathol. 2003 Dec;163(6):2337-46
references: 14633607
references: Am J Pathol. 2013 Feb;182(2):332-8
references: 23246153
references: Am J Physiol Heart Circ Physiol. 2012 Mar 15;302(6):H1241-9
references: 22227128
references: Kidney Int. 2004 Aug;66(2):571-9
references: 15253708
references: Cell Calcium. 2009 Jan;45(1):38-54
references: 18635261
references: Kidney Int. 2004 Nov;66(5):1755-65
references: 15496146
references: Am J Physiol Cell Physiol. 2009 Dec;297(6):C1379-88
references: 19794150
references: J Cell Biol. 2006 Nov 20;175(4):547-54
references: 17101696
references: Science. 2005 Jun 17;308(5729):1801-4
references: 15879175
references: Br J Pharmacol. 2006 Jun;148(3):264-73
references: 16604090
references: Nature. 1995 Nov 16;378(6554):292-5
references: 7477350
references: Nature. 2004 Jul 8;430(6996):235-40
references: 15241420
references: Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17079-86
references: 17079490
references: Nature. 2002 Feb 28;415(6875):1039-42
references: 11875573
references: Pediatr Nephrol. 2010 Feb;25(2):241-52
references: 19066979
references: J Am Soc Nephrol. 2003 Aug;14(8):2063-71
references: 12874460
references: Methods Enzymol. 2007;428:183-207
references: 17875418
references: Nat Genet. 2000 Apr;24(4):349-54
references: 10742096
references: Am J Physiol Renal Physiol. 2010 Oct;299(4):F689-701
references: 20685822
references: Am J Physiol Renal Physiol. 2001 Oct;281(4):F579-96
references: 11553505
references: Am J Physiol Renal Physiol. 2008 Jul;295(1):F235-46
references: 18480178
references: J Clin Invest. 2004 Nov;114(10):1475-83
references: 15545998
references: PLoS One. 2009 Nov 10;4(11):e7771
references: 19936226
references: Am J Physiol Renal Physiol. 2012 Feb 1;302(3):F298-307
references: 22031853
references: J Biol Chem. 2003 Feb 7;278(6):3562-71
references: 12456670
references: Mol Pharmacol. 2012 Oct;82(4):728-37
references: 22828802
references: Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16586-91
references: 17056714
references: Nat Genet. 2005 Jul;37(7):739-44
references: 15924139
references: Eur J Cell Biol. 2006 Apr;85(3-4):229-34
references: 16546566
references: Sci Signal. 2010 Oct 26;3(145):ra77
references: 20978238
references: Proc Natl Acad Sci U S A. 2013 Mar 19;110(12):E1162-8
references: 23487776
references: Trends Mol Med. 2007 Sep;13(9):396-403
references: 17766183
references: Circ Res. 2009 Jun 19;104(12):1399-409
references: 19443836
references: J Am Soc Nephrol. 2009 Mar;20(3):473-8
references: 19244577
references: Am J Physiol Renal Physiol. 2010 Sep;299(3):F594-604
references: 20630939
references: Toxicon. 2007 Feb;49(2):249-70
references: 17157345
references: J Am Soc Nephrol. 2007 Jan;18(1):29-36
references: 17167110
references: J Am Soc Nephrol. 2009 Oct;20(10):2181-9
references: 19713307
references: PLoS One. 2010 Sep 20;5(9):e12859
references: 20877463
references: Am J Physiol Cell Physiol. 2011 Mar;300(3):C397-405
references: 21123730
references: Physiol Rev. 2003 Jan;83(1):253-307
references: 12506131
references: Am J Physiol Cell Physiol. 2009 Mar;296(3):C558-69
references: 19129465
references: Am J Pathol. 2003 Sep;163(3):889-99
references: 12937130
references: Trends Cell Biol. 2007 Aug;17(8):394-402
references: 17766116
references: Mol Pharmacol. 2009 Mar;75(3):466-77
references: 19052171
references: Lab Invest. 2002 Jun;82(6):713-8
references: 12065681
references: J Am Soc Nephrol. 2011 Aug;22(8):1391-3
references: 21757772
references: Am J Physiol Renal Physiol. 2007 Dec;293(6):F1777-86
references: 17804486
references: Am J Physiol Renal Physiol. 2006 Aug;291(2):F473-80
references: 16495210
references: Hum Mol Genet. 2003 Dec 15;12(24):3397-405
references: 14570703
references: Cell Calcium. 2009 Apr;45(4):384-90
references: 19232718
references: J Biol Chem. 1979 Oct 10;254(19):9829-34
references: 489574