title: Signaling complex formation of phospholipase Cbeta4 with metabotropic glutamate receptor type 1alpha and 1,4,5-trisphosphate receptor at the perisynapse and endoplasmic reticulum in the mouse brain.
abstract: Upon activation of cell surface receptors coupled to the Gq subclass of G proteins, phospholipase C (PLC) beta hydrolyses membrane phospholipid to yield a pair of second messengers, inositol 1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol. PLCbeta4 has been characterized as the isoform enriched in cerebellar Purkinje cells (PCs) and the retina and involved in motor and visual functions. Here we examined cellular and subcellular distributions of PLCbeta4 in adult mouse brains. Immunohistochemistry showed that high levels of PLCbeta4 were detected in the somatodendritic domain of neuronal populations expressing the metabotropic glutamate receptor (mGluR) type 1alpha, including olfactory periglomerular cells, neurons in the bed nucleus anterior commissure, thalamus, substantia nigra, inferior olive, and unipolar brush cells and PCs in the cerebellum. Low to moderate levels were detected in many other mGluR1alpha-positive neurons and in a few mGluR1alpha-negative neurons. In PCs, immunogold electron microscopy localized PLCbeta4 to the perisynapse, at which mGluR1alpha is concentrated, and to the smooth endoplasmic reticulum in dendrites and spines, an intracellular Ca2+ store gated by IP3 receptors. In the cerebellum, immunoblot demonstrated its concentrated distribution in the post-synaptic density and microsomal fractions, where mGluR1alpha and type 1 IP3 receptor were also greatly enriched. Furthermore, PLCbeta4 formed coimmunoprecipitable complexes with mGluR1alpha, type 1 IP3 receptor and Homer 1. These results suggest that PLCbeta4 is preferentially localized in the perisynapse and smooth endoplasmic reticulum as a component of the physically linked phosphoinositide signaling complex. This close molecular relationship might provide PLCbeta4 with a high-fidelity effector function to mediate various neuronal responses under physiological and pathophysiological conditions.
authors.affiliation: Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Kazunori
authors.initials: K
authors.lastname: Sato
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukaya
authors.forename: Kenji
authors.initials: K
authors.lastname: Araishi
authors.forename: Atsu
authors.initials: A
authors.lastname: Aiba
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kano
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D000906:Antibodies / Q000378:metabolism; D015153:Blotting, Western; D001921:Brain / Q000166:cytology; D064026:Calbindins; D015220:Calcium Channels / Q000378:metabolism*; D037282:Calreticulin / Q000378:metabolism; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D000072233:Homer Scaffolding Proteins; D007150:Immunohistochemistry / Q000379:methods; D047468:Immunoprecipitation / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes / Q000276:immunology / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D016253:Microscopy, Immunoelectron / Q000379:methods; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure; D010320:Parvalbumins / Q000378:metabolism; D054799:Phospholipase C beta; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure; D018091:Receptors, AMPA / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D010738:Type C Phospholipases / Q000276:immunology / Q000378:metabolism*; D050598:Vesicular Glutamate Transport Protein 1
chemical_list: D000906:Antibodies; D064026:Calbindins; D015220:Calcium Channels; D037282:Calreticulin; D002352:Carrier Proteins; D000072233:Homer Scaffolding Proteins; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes; D026901:Membrane Transport Proteins; D010320:Parvalbumins; D018091:Receptors, AMPA; D018160:Receptors, Cytoplasmic and Nuclear; D018094:Receptors, Metabotropic Glutamate; D064030:S100 Calcium Binding Protein G; D050598:Vesicular Glutamate Transport Protein 1; C104723:glutamate receptor ionotropic, AMPA 3; C104077:metabotropic glutamate receptor type 1; D010738:Type C Phospholipases; D054799:Phospholipase C beta; D043802:GTP-Binding Protein alpha Subunits, Gq-G11