title: Molecular cloning and characterization of a novel phospholipase C, PLC-eta.
abstract: PLC (phospholipase C) plays an important role in intracellular signal transduction by hydrolysing phosphatidylinositol 4,5-bisphosphate, a membrane phospholipid. To date, 12 members of the mammalian PLC isoforms have been identified and classified into five isotypes beta, gamma, delta, epsilon and zeta, which are regulated by distinct mechanisms. In the present study, we describe the identification of a novel PLC isoform in the brains of human and mouse, named PLC-eta, which contains the conserved pleckstrin homology domain, X and Y domains for catalytic activity and the C2 domain. The first identified gene encoded 1002 (human) or 1003 (mouse) amino acids with an estimated molecular mass of 115 kDa. The purified recombinant PLC-eta exhibited Ca2+-dependent catalytic activity on phosphatidylinositol 4,5-bisphosphate. Furthermore, molecular biological analysis revealed that the PLC-eta gene was transcribed to several splicing variants. Although some transcripts were detected in most of the tissues we examined, the transcript encoding 115 kDa was restricted to the brain and lung. In addition, the expression of the 115 kDa protein was defined in only nerve tissues such as the brain and spinal cord. In situ hybridization analysis with brain revealed that PLC-eta was abundantly expressed in various regions including cerebral cortex, hippocampus, zona incerta and cerebellar Purkinje cell layer, which are neuronal cell-enriched regions. These results suggest that PLC-eta may perform fundamental roles in the brain.
authors.affiliation: Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Jong-Ik
authors.initials: JI
authors.lastname: Hwang
authors.forename: Yong-Seok
authors.initials: YS
authors.lastname: Oh
authors.forename: Kum-Joo
authors.initials: KJ
authors.lastname: Shin
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Ryu
authors.forename: Pann-Ghill
authors.initials: PG
authors.lastname: Suh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology; D003001:Cloning, Molecular; D020869:Gene Expression Profiling; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D054801:Phosphoinositide Phospholipase C; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D010738:Type C Phospholipases / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000378:metabolism*
chemical_list: D010738:Type C Phospholipases; C506060:PLCH1 protein, human; D054801:Phosphoinositide Phospholipase C; C506061:Plch1 protein, mouse