The Pro335 --> Leu polymorphism of type 3 inositol 1,4,5-trisphosphate receptor found in mouse inbred lines results in functional change.
Inositol 1,4,5-trisphosphate receptor (IP3R) is an intracellular Ca2+ channel involved in various cellular signaling. Type 3 IP3R (IP3R3) retains ligand-gated Ca2+ channel properties differing from other subtypes in terms of IP3-binding affinity and regulation of its channel activity by effector molecules. In this study, we found the natural Pro335 --> Leu polymorphism of mouse IP3R3 between BALB/c and C57BL/6J. We investigated the functional differences between Pro335IP3R3 and Leu335IP3R3 with purified receptors reconstituted into proteoliposomes as well as with soluble ligand binding domains. Pro335IP3R3 exhibited significantly higher IP3-binding affinity and IP3-induced Ca2+ release than those of Leu335IP3R3 in both forms of the receptor. Moreover, the polymorphic change caused differences in the effect of external Ca2+ on IP3-induced Ca2+ release. The Pro335 --> Leu substitution alters the conformation of soluble ligand binding domain as revealed by intrinsic fluorescence and circular dichroism spectra with or without Ca2+. The results indicate that the polymorphism of IP3R3 causes changes in receptor function, presumably affecting intracellular Ca2+ signaling.
Kim
Sanghyeon
S
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yusong-gu, Daejeon.
Ahn
Taeho
T
Park
Chankyu
C
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry* / Q000235:genetics*; D002942:Circular Dichroism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005456:Fluorescent Dyes / Q000494:pharmacology; D005822:Genetic Vectors; D005982:Glutathione Transferase / Q000378:metabolism; D006639:Histidine / Q000737:chemistry; D047468:Immunoprecipitation; D007211:Indoles / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007413:Intestinal Mucosa / Q000378:metabolism; D007700:Kinetics; D007930:Leucine / Q000737:chemistry*; D008024:Ligands; D008081:Liposomes / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011110:Polymorphism, Genetic; D011392:Proline / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011510:Proteolipids / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000235:genetics*; D011994:Recombinant Proteins / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence
D015220:Calcium Channels; D018076:DNA, Complementary; D005456:Fluorescent Dyes; D007211:Indoles; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008024:Ligands; D008081:Liposomes; D011510:Proteolipids; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; C020485:proteoliposomes; D006639:Histidine; D011392:Proline; D005982:Glutathione Transferase; D007930:Leucine; C048960:indo-1; D002118:Calcium