title: Diacylglycerol kinase ε localizes to subsurface cisterns of cerebellar Purkinje cells.
abstract: Following activation of Gq protein-coupled receptors, phospholipase C yields a pair of second messengers: diacylglycerol (DG) and inositol 1,4,5-trisphosphate. Diacylglycerol kinase (DGK) phosphorylates DG to produce phosphatidic acid, another second messenger. Of the DGK family, DGKε is the only DGK isoform that exhibits substrate specificity for DG with an arachidonoyl acyl chain at the sn-2 position. Recently, we demonstrated that hydrophobic residues in the N-terminus of DGKε play an important role in targeting the endoplasmic reticulum in transfected cells. However, its cellular expression and subcellular localization in the brain remain elusive. In the present study, we investigate this issue using specific DGKε antibody. DGKε was richly expressed in principal neurons of higher brain regions, including pyramidal cells in the hippocampus and neocortex, medium spiny neurons in the striatum and Purkinje cells in the cerebellum. In Purkinje cells, DGKε was localized to the subsurface cisterns and colocalized with inositol 1,4,5-trisphosphate receptor-1 in dendrites and axons. In dendrites of Purkinje cells, DGKε was also distributed in close apposition to DG lipase-α, which catalyzes arachidonoyl-DG to produce 2-arachidonoyl glycerol, a major endocannabinoid in the brain. Behaviorally, DGKε-knockout mice exhibited hyper-locomotive activities and impaired motor coordination and learning. These findings suggest that DGKε plays an important role in neuronal and brain functions through its distinct neuronal expression and subcellular localization and also through coordinated arrangement with other molecules involving the phosphoinositide signaling pathway.
authors.affiliation: Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Hondo 1-1-1, Akita, 010-8543, Japan. yahodumi@med.akita-u.ac.jp.|Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata, 990-9585, Japan. yahodumi@med.akita-u.ac.jp.
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Hozumi
authors.affiliation: Department of Physiology, Yamagata University School of Medicine, Yamagata, 990-9585, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Physiology, Yamagata University School of Medicine, Yamagata, 990-9585, Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Kaneko
authors.affiliation: Department of Physiology, Yamagata University School of Medicine, Yamagata, 990-9585, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujii
authors.affiliation: Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, UT 84112, USA.
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Topham
authors.affiliation: Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata, 990-9585, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Goto
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D002531:Cerebellum / Q000166:cytology / Q000201:enzymology* / Q000648:ultrastructure; D019852:Diacylglycerol Kinase / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D007858:Learning; D008124:Locomotion; D051379:Mice; D018345:Mice, Knockout; D016716:PC12 Cells; D010716:Phosphatidylinositols / Q000378:metabolism; D011597:Psychomotor Performance; D011689:Purkinje Cells / Q000201:enzymology* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D015290:Second Messenger Systems; D014018:Tissue Distribution
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; C488910:Itpr1 protein, rat; D010716:Phosphatidylinositols; D019852:Diacylglycerol Kinase
keywords: Behavior; Immunohistochemistry; Inositol 1,4,5-trisphosphate receptor; Knockout mouse; Rat brain