J Biol Chem. 2006 Oct 27;281(43):32540-9. Epub 2006 Aug 3.

Homer 1 mediates store- and inositol 1,4,5-trisphosphate receptor-dependent translocation and retrieval of TRPC3 to the plasma membrane.External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c

Kim, J. Y., Zeng, W., Kiselyov, K., Yuan, J. P., Dehoff, M. H., Mikoshiba, K., Worley, P. F., Muallem, S.,
["Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA."]
Store-operated Ca(2+) channels (SOCs) mediate receptor-stimulated Ca(2+) influx. Accumulating evidence indicates that members of the transient receptor potential (TRP) channel family are components of SOCs in mammalian cells. Agonist stimulation activates SOCs and TRP channels directly and by inducing translocation of channels in intracellular vesicles to the plasma membrane (PM). The mechanism of TRP channel translocation in response to store depletion and agonist stimulation is not known. Here we use TRPC3 as a model to show that IP(3) and the scaffold Homer 1 (H1) regulate the rate of translocation and retrieval of TRPC3 from the PM. In resting cells, TRPC3 exists in TRPC3-H1b/c-IP(3)Rs complexes that are located in part at the PM and in part in intracellular vesicles. Binding of IP(3) to the IP(3)Rs dissociates the interaction between IP(3)Rs and H1 but not between H1 and TRPC3 to form IP(3)Rs-TRPC3-H1b/c. TIRFM and biotinylation assays show robust receptor- and store-dependent translocation of the TRPC3 to the PM and their retrieval upon termination of cell stimulation. The translocation requires depletion of stored Ca(2+) and is prevented by inhibition of the IP(3)Rs. In HEK293, dissociating the H1b/c-IP(3)R complex with H1a results in TRPC3 translocation to the PM, where it is spontaneously active. The TRPC3-H1b/c-IP(3)Rs complex is reconstituted by infusing H1c into these cells. Reconstitution is inhibited by IP(3). Deletion of H1 in mice markedly reduces the rates of translocation and retrieval of TRPC3. Conversely, infusion of H1c into H1(-/-) cells eliminates spontaneous channel activity and increases the rate of channel activation by agonist stimulation. The effects of H1c are inhibited by IP(3). These findings together with our earlier studies demonstrating gating of TRPC3 by IP(3)Rs were used to develop a model in which assembly of the TRPC3-H1b/c-IP(3)Rs complexes by H1b/c mediates both the translocation of TRPC3-containing vesicles to the PM and gating of TRPC3 by IP(3)Rs.
PMID: 16887806External 2231691f894ba696de1310221b0a0dbbb31a7251e75115c265587c3d9d5f507c
Screening Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
  Experimental screening Non-experimental screening Reference
TRP channel construct Interactor source
TRP channel Interactor Method Species Region Species Organ/tissue Sample type
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Homer-1 Inference Prediction 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 PMCA Speculation Prediction 16887806
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
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
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Homer-1 Fusion protein-pull down assay Human Full-length HEK293 lysates Human Full-length E. coli 16887806
(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
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 IP3R3 Co-immunofluorescence staining Mouse pancreatic acini 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 IP3R3 Co-immunofluorescence staining Mouse parotid acini 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 IP3R3 Co-immunofluorescence staining Mouse submandibular gland duct 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 IP3R3 Co-immunoprecipitation Mouse brain tissue 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 IP3R3 Co-immunoprecipitation Mouse pancreatic tissue 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 IP3R3 Co-immunoprecipitation Mouse submandibular gland lysates 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 PMCA Co-immunoprecipitation Mouse brain tissue 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 PMCA Co-immunoprecipitation Mouse pancreatic tissue 16887806
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
Functional consequence Toggle 893349bafcc528f8346c51dc3420151d67b0126b2c122dd1017121c03fa0f69b
TRP channel Interactor Method Post-translational modification Subcellular trafficking Activity Reference
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Homer-1 Patch clamp Activation 16887806
TRPC3 Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4 Homer-1 Cell surface biotinylation Increase in plasma membrane level 16887806
(Link 2bd4d11adb659cddf58197a94e201f0a44c55d8d7cb427c624971b42e122c0a4: click the arrow icon to show interactions only between the corresponding TRP channel and the interactor)
TRP / Interactor

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