The N-terminal domain of the IP3 receptor gates store-operated hTrp3 channels.
In the present work, we studied the interaction and effect of several IP3 receptor (IP3R) constructs on the gating of the store-operated (SOC) hTrp3 channel. Full-length IP3R coupled to silent hTrp3 channels in intact cells but did not activate them until stores were depleted of Ca2+. By contrast, constructs containing the IP3-binding domain activated silent hTrp3 channels in unstimulated cells and restored gating of hTrp3 by IP3 in excised plasma membrane patches. We conclude that the N-terminal domain of the IP3R functions as a gate and is sufficient for activation of SOCs. The sensing and transduction domains of the IP3R are required to maintain SOCs in an inactive state.
Kiselyov
K
K
Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235, USA.
Mignery
G A
GA
Zhu
M X
MX
Muallem
S
S
D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors; D015640:Ion Channel Gating; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D050052:TRPC Cation Channels
D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D010446:Peptide Fragments; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D002118:Calcium