Dynamic interaction of hTRPC6 with the Orai1-STIM1 complex or hTRPC3 mediates its role in capacitative or non-capacitative Ca(2+) entry pathways.
TRPC (canonical transient receptor potential) channel subunits have been shown to assemble into homo- or hetero-meric channel complexes, including different Ca2+-handling proteins, required for the activation of CCE (capacitative Ca2+ entry) or NCCE (non-CCE) pathways. In the present study we found evidence for the dynamic interaction between endogenously expressed hTRPC6 (human TRPC6) with either both Orai1 and STIM1 (stromal interaction molecule 1) or hTRPC3 to participate in CCE or NCCE. Electrotransjection of cells with an anti-hTRPC6 antibody, directed towards the C-terminal region, reduces CCE induced by TPEN [N,N,N',N'-tetrakis-(2-pyridylmethyl)-ethylenediamine], which reduces the intraluminal free Ca2+ concentration. Cell stimulation with thrombin or extensive Ca2+-store depletion by TG (thapsigargin)+ionomycin enhanced the interaction between hTRPC6 and the CCE proteins Orai1 and STIM1. In contrast, stimulation with the diacylglycerol analogue OAG (1-oleoyl-2-acetyl-sn-glycerol) displaces hTRPC6 from Orai1 and STIM1 and enhances the association between hTRPC6 and hTRPC3. The interaction between hTRPC6 and hTRPC3 was abolished by dimethyl-BAPTA [1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid] loading, which indicates that this phenomenon is Ca2+-dependent. These findings support the hypothesis that hTRPC6 participates both in CCE and NCCE through its interaction with the Orai1-STIM1 complex or hTRPC3 respectively.
Jardin
Isaac
I
Department of Physiology, University of Extremadura, Caceres, Spain.
Gómez
Luis J
LJ
Salido
Gines M
GM
Rosado
Juan A
JA
D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002470:Cell Survival / Q000502:physiology; D002614:Chelating Agents / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005029:Ethylenediamines / Q000494:pharmacology; D006801:Humans; D047468:Immunoprecipitation; D015759:Ionomycin / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D000071740:ORAI1 Protein; D011485:Protein Binding / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels / Q000378:metabolism*; D000074287:TRPC6 Cation Channel; D019284:Thapsigargin / Q000494:pharmacology
C520323:1-oleoyl-2-acetoyl-sn-glycerol; D015220:Calcium Channels; D002614:Chelating Agents; D004075:Diglycerides; D005029:Ethylenediamines; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; C103530:STIM1 protein, human; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; D004533:Egtazic Acid; D015759:Ionomycin; D019284:Thapsigargin; C058180:5,5'-dimethyl-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetate; C044387:N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine; D002118:Calcium