Discrimination of intracellular calcium store subcompartments using TRPV1 (transient receptor potential channel, vanilloid subfamily member 1) release channel activity.
The store-operated calcium-release-activated calcium current, I (CRAC), is a major mechanism for calcium entry into non-excitable cells. I (CRAC) refills calcium stores and permits sustained calcium signalling. The relationship between inositol 1,4,5-trisphosphate receptor (InsP(3)R)-containing stores and I (CRAC) is not understood. A model of global InsP(3)R store depletion coupling with I (CRAC) activation may be simplistic, since intracellular stores are heterogeneous in their release and refilling activities. Here we use a ligand-gated calcium channel, TRPV1 (transient receptor potential channel, vanilloid subfamily member 1), as a new tool to probe store heterogeneity and define intracellular calcium compartments in a mast cell line. TRPV1 has activity as an intracellular release channel but does not mediate global calcium store depletion and does not invade a store coupled with I (CRAC). Intracellular TRPV1 localizes to a subset of the InsP(3)R-containing stores. TRPV1 sensitivity functionally subdivides the InsP(3)-sensitive store, as does heterogeneity in the sarcoplasmic/endoplasmic-reticulum Ca(2+)-ATPase isoforms responsible for store refilling. These results provide unequivocal evidence that a specific 'CRAC store' exists within the InsP(3)-releasable calcium stores and describe a novel methodology for manipulation of intracellular free calcium.
Turner
Helen
H
Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, USA.
Fleig
Andrea
A
Stokes
Alexander
A
Kinet
Jean-Pierre
JP
Penner
Reinhold
R
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002211:Capsaicin / Q000494:pharmacology*; D002217:Carbachol / Q000494:pharmacology; D003600:Cytosol / Q000502:physiology; D005822:Genetic Vectors; D053496:Inositol 1,4,5-Trisphosphate Receptors; D015471:Leukemia, Basophilic, Acute; D008954:Models, Biological; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D011955:Receptors, Drug / Q000187:drug effects / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D050052:TRPC Cation Channels; D050916:TRPV Cation Channels; D014162:Transfection; D014407:Tumor Cells, Cultured; D014616:Vaccinia virus / Q000235:genetics
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D011955:Receptors, Drug; D011994:Recombinant Proteins; D050052:TRPC Cation Channels; D050916:TRPV Cation Channels; C494484:TRPV1 receptor; C096351:transient receptor potential cation channel, subfamily C, member 1; D002217:Carbachol; D002211:Capsaicin; D002118:Calcium