title: Muscle-specific mRNA isoform encodes a protein composed mainly of the N-terminal 175 residues of type 2 Ins(1,4,5)P3 receptor.
abstract: We have found a novel isoform of the mouse type 2 Ins(1,4,5)P3 receptor [Ins(1,4,5)P3R] mRNA by reverse transcriptase-mediated PCR analysis. The novel isoform, which was expressed specifically in skeletal muscle and heart, was generated by the inclusion of a novel exon. As this exon contains a stop codon, the isoform encodes a putative protein (designated TIPR) consisting of 175 acid residues of the type 2 Ins(1,4,5)P3R and the following six residues derived from this exon. We transfected the cDNA of this isoform into COS-7 cells; these cells expressed a 24 kDa protein that was recognized by an antibody against TIPR produced in Escherichia coli. The isoform encoding TIPR was also found in human skeletal muscle and heart. The N-terminal region of Ins(1,4,5)P3R is suggested to have a role in ligand binding and to interact with the C-terminal channel domain of Ins(1,4,5)P3R itself. TIPR might regulate the Ins(1,4,5)P3 signal pathway in both muscles.
authors.affiliation: CNS Research Laboratories, Shionogi & Co. Ltd., 2-5-1 Mishima, Settsu-shi, Osaka 566-0022, Japan. Shirokanedai, Minato-ku, Tokyo 108-8639,
authors.forename: A
authors.initials: A
authors.lastname: Futatsugi
authors.forename: G
authors.initials: G
authors.lastname: Kuwajima
authors.forename: K
authors.initials: K
authors.lastname: Mikoshiba
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D015220:Calcium Channels / Q000737:chemistry / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007438:Introns; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D015220:Calcium Channels; D017931:DNA Primers; D018076:DNA, Complementary; C506926:ITPR1 protein, human; C506927:ITPR2 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D015544:Inositol 1,4,5-Trisphosphate