title: Identification of rabaptin-5, rabex-5, and GM130 as putative effectors of rab33b, a regulator of retrograde traffic between the Golgi apparatus and ER.
abstract: The role of rab33b, a Golgi-specific rab protein, was investigated. Microinjection of rab33b mutants stabilised in the GTP-specific state resulted in a marked inhibition of anterograde transport within the Golgi and in the recycling of glycosyltransferases from the Golgi to the ER, respectively. A GST-rab33b fusion protein stabilised in its GTP form was found to interact by Western blotting or mass spectroscopy with Golgi protein GM130 and rabaptin-5 and rabex-5, two rab effector molecules thought to function exclusively in the endocytic pathway. A similar binding was seen to rab1 but not to rab6, both Golgi rabs. In contrast, rab5 was as expected, shown to bind rabaptin-5 and rabex-5 as well as the endosomal effector protein EEA1 but not GM130. No binding of EEA1 was seen to any of the Golgi rabs.
authors.affiliation: Cell Biology and Biophysics Programme, EMBL, Heidelberg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Valsdottir
authors.forename: H
authors.initials: H
authors.lastname: Hashimoto
authors.forename: K
authors.initials: K
authors.lastname: Ashman
authors.forename: T
authors.initials: T
authors.lastname: Koda
authors.forename: B
authors.initials: B
authors.lastname: Storrie
authors.forename: T
authors.initials: T
authors.lastname: Nilsson
mesh_terms: D000818:Animals; D001324:Autoantigens; D001693:Biological Transport, Active; D015153:Blotting, Western; D001921:Brain; D002417:Cattle; D003600:Cytosol / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D008099:Liver; D013058:Mass Spectrometry; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism*; D009154:Mutation; D011233:Precipitin Tests; D011485:Protein Binding; D021381:Protein Transport; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D033921:Vesicular Transport Proteins; D014759:Viral Envelope Proteins / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D001324:Autoantigens; C028391:G protein, vesicular stomatitis virus; C097741:Golgin subfamily A member 2; D020662:Guanine Nucleotide Exchange Factors; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C097227:RABEP1 protein, human; C108382:RABGEF1 protein, human; C486276:Rabep1 protein, mouse; D011993:Recombinant Fusion Proteins; D033921:Vesicular Transport Proteins; D014759:Viral Envelope Proteins; D006160:Guanosine Triphosphate; C486397:RAB33B protein, human; D020691:rab GTP-Binding Proteins