Abstract
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.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Calcium / metabolism*
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Calcium Channels / genetics
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Calcium Channels / metabolism*
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Humans
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Inositol 1,4,5-Trisphosphate Receptors
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Ion Channel Gating*
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Patch-Clamp Techniques
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Peptide Fragments / genetics
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Peptide Fragments / metabolism
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Protein Conformation
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Receptors, Cytoplasmic and Nuclear / genetics
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Receptors, Cytoplasmic and Nuclear / metabolism*
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Recombinant Proteins / metabolism
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TRPC Cation Channels
Substances
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Calcium Channels
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ITPR1 protein, human
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Inositol 1,4,5-Trisphosphate Receptors
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Peptide Fragments
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Receptors, Cytoplasmic and Nuclear
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Recombinant Proteins
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TRPC Cation Channels
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transient receptor potential cation channel, subfamily C, member 1
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Calcium