A new splice variant of the inositol-1,4,5-triphosphate (IP3) receptor.
In this study we have identified a new splice variant of the IP3 receptor (IP3R) transcript in a number of mouse cell lines (e.g. mouse T-lymphoma cells, mouse splenic lymphocytes and mouse NIH 3T3 fibroblast cell lines) using the reverse transcriptase-polymerase chain reaction. This variant IP3 receptor (designated as IP3RV-S2, approximately 453 bp) is larger than the non-neuronal form (402 bp) but smaller than the neuronal form (522 bp) of the IP3 receptors. Nucleotide sequencing data indicate that this new isoform (IP3RV-S2) contains a 51 nucleotide insertion within the non-neuronal form of IP3R at the S2 splice site. During mitogenic stimulation by Con A, the ratio between IP3R (non-neuronal form) and IP3RV-S2 (variant isoform) in mouse splenic T-lymphocytes increases approximately 1.5-fold. The change in relative amounts of these two IP3 receptor isoforms during mitogenic-stimulation suggests that T-lymphocytes may have different requirements for the IP3 isoforms in order to control intracellular calcium mobilization. The selective expression of these two IP3R isoforms (IP3RV-S2 and non-neuronal IP3R) may be critically important for the onset of signal transduction and cell activation.
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Department of Cell Biology and Anatomy, School of Medicine, University of Miami, FL 33101.
Bourguignon
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D000818:Animals; D001483:Base Sequence; D001921:Brain; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology; D017931:DNA Primers; D004274:DNA, Recombinant; D014644:Genetic Variation; D015544:Inositol 1,4,5-Trisphosphate / Q000235:genetics* / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D017931:DNA Primers; D004274:DNA, Recombinant; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D003208:Concanavalin A; D015544:Inositol 1,4,5-Trisphosphate