title: Transport of soluble proteins through the Golgi occurs by diffusion via continuities across cisternae.
abstract: The mechanism of transport through the Golgi complex is not completely understood, insofar as no single transport mechanism appears to account for all of the observations. Here, we compare the transport of soluble secretory proteins (albumin and α1-antitrypsin) with that of supramolecular cargoes (e.g., procollagen) that are proposed to traverse the Golgi by compartment progression-maturation. We show that these soluble proteins traverse the Golgi much faster than procollagen while moving through the same stack. Moreover, we present kinetic and morphological observations that indicate that albumin transport occurs by diffusion via intercisternal continuities. These data provide evidence for a transport mechanism that applies to a major class of secretory proteins and indicate the co-existence of multiple intra-Golgi trafficking modes.
authors.affiliation: Fondazione IFOM, Istituto FIRC di Oncologia Molecolare (IFOM-IEO Campus), Milan, Italy.
authors.forename: Galina V
authors.initials: GV
authors.lastname: Beznoussenko
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Seetharaman
authors.initials: S
authors.lastname: Parashuraman
authors.affiliation: Institute of Protein Biochemistry, Consiglio Nazionale Delle Ricerche (CNR-IBP), Naples, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Rizzo
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Roman
authors.initials: R
authors.lastname: Polishchuk
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Oliviano
authors.initials: O
authors.lastname: Martella
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Di Giandomenico
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Aurora
authors.initials: A
authors.lastname: Fusella
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Alexander
authors.initials: A
authors.lastname: Spaar
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Sallese
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Capestrano
authors.affiliation: Department of Cell Biology and Ultrastructure Research, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria.
authors.forename: Margit
authors.initials: M
authors.lastname: Pavelka
authors.affiliation: FEI Company, Eindhoven, Netherlands.
authors.forename: Matthijn R
authors.initials: MR
authors.lastname: Vos
authors.affiliation: FEI Company, Eindhoven, Netherlands.
authors.forename: Yuri G M
authors.initials: YG
authors.lastname: Rikers
authors.affiliation: Center for Bioinformatics, Saarland University, Saarbruecken, Germany.
authors.forename: Volkhard
authors.initials: V
authors.lastname: Helms
authors.affiliation: Fondazione IFOM, Istituto FIRC di Oncologia Molecolare (IFOM-IEO Campus), Milan, Italy.
authors.forename: Alexandre A
authors.initials: AA
authors.lastname: Mironov
authors.affiliation: Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Luini
mesh_terms: D000418:Albumins / Q000378:metabolism*; D001692:Biological Transport; D003198:Computer Simulation; D004058:Diffusion; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D008027:Light; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D018715:Microscopy, Video; D021381:Protein Transport; D000515:alpha 1-Antitrypsin / Q000378:metabolism*
chemical_list: D000418:Albumins; D000515:alpha 1-Antitrypsin; D049452:Green Fluorescent Proteins
keywords: albumin; cell biology; golgi complex; human; intracellular trafficking; membrane tubules; soluble cargo proteins