J Biol Chem. 2000 Nov 24;275(47):36483-6.
Expression of truncated transient receptor potential protein 1alpha (Trp1alpha ): evidence that the Trp1 C terminus modulates store-operated Ca2+ entry.
Singh, B. B., Liu, X., Ambudkar, I. S.,
["Secretory Physiology Section, Gene Therapy and Therapeutics Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA."]
["Secretory Physiology Section, Gene Therapy and Therapeutics Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA."]
Transient receptor potential protein 1 (Trp1) has been proposed as a component of the store-operated Ca(2+) entry (SOCE) channel. However, the exact mechanism by which Trp1 is regulated by store depletion is not known. Here, we examined the role of the Trp1 C-terminal domain in SOCE by expressing hTrp1alpha lacking amino acids 664-793 (DeltaTrp1alpha) or full-length hTrp1alpha in the HSG (human submandibular gland) cell line. Both carbachol (CCh) and thapsigargin (Tg) activated sustained Ca(2+) influx in control (nontransfected), DeltaTrp1alpha-, and Trp1alpha-expressing cells. Sustained [Ca(2+)](i), following stimulation with either Tg or CCh in DeltaTrp1alpha-expressing cells, was about 1.5-2-fold higher than in Trp1alpha-expressing cells and 4-fold higher than in control cells. Importantly, (i) basal Ca(2+) influx and (ii) Tg- or CCh-stimulated internal Ca(2+) release were similar in all the cells. A similar increase in Tg-stimulated Ca(2+) influx was seen in cells expressing Delta2Trp1alpha, lacking the C-terminal domain amino acid 649-793, which includes the EWKFAR sequence. Further, both inositol 1,4,5-trisphosphate receptor-3 and caveolin-1 were immunoprecipitated with DeltaTrp1alpha and Trp1alpha. In aggregate, these data suggest that (i) the EWKFAR sequence does not contribute significantly to the Trp1-associated increase in SOCE, and (ii) the Trp1 C-terminal region, amino acids 664-793, is involved in the modulation of SOCE.
PMID: 10980191
 Screening
Validation: In vitro validation
Validation: In vivo validation
Characterization
Functional consequence
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Validation: In vivo validation
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| 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 |
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Caveolin-1 | Co-immunoprecipitation | HSG cell | Human | Full-length | Not used | 10980191 | ||
| TRPC1 |
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IP3R3 | Co-immunoprecipitation | HSG cell | Human | Full-length | Not used | 10980191 | ||
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:
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