title: Regulation of human Dicer by the resident ER membrane protein CLIMP-63.
abstract: The ribonuclease Dicer plays a central role in the microRNA pathway by catalyzing the formation of microRNAs, which are known to regulate messenger RNA (mRNA) translation. In order to improve our understanding of the molecular context in which Dicer functions and how it is regulated in human cells, we sought to expand its protein interaction network by employing a yeast two-hybrid screening strategy. This approach led to the identification and characterization of cytoskeleton-linking endoplasmic reticulum (ER) membrane protein of 63 kDa (CLIMP-63) as a novel Dicer-interacting protein. CLIMP-63 interacts with Dicer to form a high molecular weight complex, which is electrostatic in nature, is not mediated by RNA and is catalytically active in pre-microRNA processing. CLIMP-63 is required for stabilizing Dicer protein and for optimal regulation of a reporter gene coupled to the 3' untranslated region of HMGA2 mRNA in human cells. Interacting with a portion of the luminal domain of CLIMP-63 and within minutes of its synthesis, our results suggest that Dicer transits through the ER, is glycosylated and can be secreted by cultured human cells with CLIMP-63. Our findings define CLIMP-63 as a novel protein interactor and regulator of Dicer function, involved in maintaining Dicer protein levels in human cells.
authors.affiliation: CHUQ Research Center/CHUL, 2705 Blvd Laurier, QC, G1V 4G2, Canada.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Pépin
authors.forename: Marjorie P
authors.initials: MP
authors.lastname: Perron
authors.forename: Patrick
authors.initials: P
authors.lastname: Provost
mesh_terms: D053487:DEAD-box RNA Helicases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D004795:Enzyme Stability; D006031:Glycosylation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D035683:MicroRNAs / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D034622:RNA Interference; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D043244:Ribonuclease III / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*
chemical_list: C081876:CKAP4 protein, human; D008565:Membrane Proteins; D035683:MicroRNAs; D012322:RNA Precursors; C408087:DICER1 protein, human; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases