title: Differential inositol 1,4,5-trisphosphate receptor signaling in a neuronal cell line.
abstract: Differential intracellular distribution of the three pharmacologically and biophysically distinct types of IP3Rs can lead to different subcellular Ca2+ transients each coupled to discrete intracellular functions. Here, we report the functional localization of differentially distributed IP3 receptor types in the commonly-used hippocampal cell line HT22. The distinct subcellular localization and Ca2+ signaling properties of these receptors determine the potential role of specific IP3 receptor types in cellular function. By utilizing immunochemistry, we conclude that HT22 cells express all three IP3 receptors with types 1 and 3 being expressed predominantly in the endoplasmic reticulum and perinuclear regions and type 2 being expressed predominantly in the nuclear envelope. Optical imaging studies using the Ca2+-sensitive indicator dye fluo-3 show that nuclear IP3 responses have greater amplitude and faster kinetics than cytosolic IP3 responses corresponding to the biophysical characteristics of the differentially distributed receptor types. These results support the hypothesis that differentially distributed IP3R isotypes mediate distinct cellular functions through differential, organelle-specific Ca2+ signaling.
authors.affiliation: Department of Pharmacology and Neuroscience, Institute for Aging and Alzheimer's Disease Research, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107, United States.
authors.forename: R Scott
authors.initials: RS
authors.lastname: Duncan
authors.forename: Sung-Yong
authors.initials: SY
authors.lastname: Hwang
authors.forename: Peter
authors.initials: P
authors.lastname: Koulen
mesh_terms: D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000819:agonists / Q000378:metabolism / Q000502:physiology*; D047028:Macrocyclic Compounds / Q000494:pharmacology; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010080:Oxazoles / Q000494:pharmacology; D020033:Protein Isoforms / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014018:Tissue Distribution; D014966:Xanthenes / Q000494:pharmacology
chemical_list: D000814:Aniline Compounds; D053496:Inositol 1,4,5-Trisphosphate Receptors; D047028:Macrocyclic Compounds; D010080:Oxazoles; D020033:Protein Isoforms; D014966:Xanthenes; C108642:xestospongin D; C059715:Fluo-3; D002118:Calcium