J Biol Chem. 2007 Mar 23;282(12):9105-16. Epub 2007 Jan 15.

Dynamic assembly of TRPC1-STIM1-Orai1 ternary complex is involved in store-operated calcium influx. Evidence for similarities in store-operated and calcium release-activated calcium channel components.External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c

Ong, H. L., Cheng, K. T., Liu, X., Bandyopadhyay, B. C., Paria, B. C., Soboloff, J., Pani, B., Gwack, Y., Srikanth, S., Singh, B. B., Gill, D. L., Ambudkar, I. S.,
["Secretory Physiology Section, Gene Therapy and Therapeutics Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA."]
Store-operated calcium entry (SOCE) is a ubiquitous mechanism that is mediated by distinct SOC channels, ranging from the highly selective calcium release-activated Ca2+ (CRAC) channel in rat basophilic leukemia and other hematopoietic cells to relatively Ca2+-selective or non-selective SOC channels in other cells. Although the exact composition of these channels is not yet established, TRPC1 contributes to SOC channels and regulation of physiological function of a variety of cell types. Recently, Orai1 and STIM1 have been suggested to be sufficient for generating CRAC channels. Here we show that Orai1 and STIM1 are also required for TRPC1-SOC channels. Knockdown of TRPC1, Orai1, or STIM1 attenuated, whereas overexpression of TRPC1, but not Orai1 or STIM1, induced an increase in SOC entry and I(SOC) in human salivary gland cells. All three proteins were co-localized in the plasma membrane region of cells, and thapsigargin increased co-immunoprecipitation of TRPC1 with STIM1, and Orai1 in human salivary gland cells as well as dispersed mouse submandibular gland cells. In aggregate, the data presented here reveal that all three proteins are essential for generation of I(SOC) in these cells and that dynamic assembly of TRPC1-STIM1-Orai1 ternary complex is involved in activation of SOC channel in response to internal Ca2+ store depletion. Thus, these data suggest a common molecular basis for SOC and CRAC channels.
PMID: 17224452External 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 STIM1 Fusion protein-pull down assay Not specified 1-347 E. coli Not used HSG cell lysates 17224452
(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 STIM1 Co-immunofluorescence staining HSG cell Human Full-length Not specified Full-length 17224452
TRPC1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 STIM1 Co-immunoprecipitation HEK293 Not used Not specified Full-length 17224452
TRPC1 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 STIM1 Co-immunoprecipitation A7r5 Not used Not specified Full-length 17224452
(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 STIM1 Fusion protein-pull down assay Human 1-347 Human Not determined 17224452
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
TRP / Interactor

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