J Biol Chem. 2005 Jun 3;280(22):21600-6. Epub 2005 Apr 17.

Molecular analysis of a store-operated and 2-acetyl-sn-glycerol-sensitive non-selective cation channel. Heteromeric assembly of TRPC1-TRPC3.External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c

Liu, X., Bandyopadhyay, B. C., Singh, B. B., Groschner, K., Ambudkar, I. S.,
["Secretory Physiology Section, Gene Therapy and Therapeutics Branch, NIDCR, National Institutes of Health, DHHS, Bethesda, Maryland 20892, USA."]
We have reported that internal Ca2+ store depletion in HSY cells stimulates a nonselective cation current which is distinct from I(CRAC) in RBL cells and TRPC1-dependent I(SOC) in HSG cells (Liu, X., Groschner, K., and Ambudkar, I. S. (2004) J. Membr. Biol. 200, 93-104). Here we have analyzed the molecular composition of this channel. Both thapsigargin (Tg) and 2-acetyl-sn-glycerol (OAG) stimulated similar non-selective cation currents and Ca2+ entry in HSY cells. The effects of Tg and OAG were not additive. HSY cells endogenously expressed TRPC1, TRPC3, and TRPC4 but not TRPC5 or TRPC6. Immunoprecipitation of TRPC1 pulled down TRPC3 but not TRPC4. Conversely, TRPC1 co-immunoprecipitated with TRPC3. Expression of antisense TRPC1 decreased (i) Tg- and OAG-stimulated currents and Ca2+ entry and (ii) the level of endogenous TRPC1 but not TRPC4. Antisense TRPC3 similarly reduced Ca2+ entry and endogenous TRPC3. Yeast two-hybrid analysis revealed an interaction between NTRPC1 and NTRPC3 (CTRPC1-CTRPC3, CTRPC3-CTRPC1, or CTRPC1-NTRPC3 did not interact), which was confirmed by glutathione S-transferase (GST) pull-down assays (GST-NTRPC3 pulled down TRPC1 and vice versa). Expression of NTRPC1 or NTRPC3 induced similar dominant suppression of Tg- and OAG-stimulated Ca2+ entry. NTRPC3 did not alter surface expression of TRPC1 or TRPC3 but disrupted TRPC1-TRPC3 association. In aggregate, our data demonstrate that TRPC1 and TRPC3 co-assemble, via N-terminal interactions, to form a heteromeric store-operated non-selective cation channel in HSY cells. Thus selective association between TRPCs generate distinct store-operated channels. Diversity of store-operated channels might be related to the physiology of the different cell types.
PMID: 15834157External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c
Validation: In vitro validation Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Assay with recombinant proteins Reference
TRP channel construct Interactor construct
TRP channel Interactor Method Species Region Expression system Species Region Expression system
TRPC1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC3 Yeast two-hybrid Not specified 1-347 Yeast Not specified 642-842 Yeast 15834157
TRPC1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC3 Fusion protein-pull down assay Not specified 1-347 E. coli Not specified Full-length HEK293 lysates 15834157
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC1 Yeast two-hybrid Not specified 642-842 Yeast Not specified 642-842 Yeast 15834157
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC1 Fusion protein-pull down assay Not specified Full-length HEK293 lysates Not specified 1-347 E. coli 15834157
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Validation: In vivo validation Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Assay with endogenous proteins Assay with overexpressed proteins Reference
Cell or tissue Cell or tissue TRP channel construct Interactor construct
TRP channel Interactor Method Species Region Species Region
TRPC1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC3 Co-immunoprecipitation HSY cell 15834157
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC1 Co-immunoprecipitation HSY cell 15834157
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Characterization Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Binding region mapping Stoichiometry Affinity (Kd) Reference
TRP channel Interactor
TRP channel Interactor Method Species Region Species Region
TRPC1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC3 Yeast two-hybrid Not specified 1-73 Not specified 1-341 15834157
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 TRPC1 Yeast two-hybrid Not specified 1-341 Not specified 1-73 15834157
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
TRP / Interactor

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