title: Actin remodeling by ADF/cofilin is required for cargo sorting at the trans-Golgi network.
abstract: Knockdown of the actin-severing protein actin-depolymerizing factor (ADF)/cofilin inhibited export of an exogenously expressed soluble secretory protein from Golgi membranes in Drosophila melanogaster and mammalian tissue culture cells. A stable isotope labeling by amino acids in cell culture mass spectrometry-based protein profiling revealed that a large number of endogenous secretory proteins in mammalian cells were not secreted upon ADF/cofilin knockdown. Although many secretory proteins were retained, a Golgi-resident protein and a lysosomal hydrolase were aberrantly secreted upon ADF/cofilin knockdown. Overall, our findings indicate that inactivation of ADF/cofilin perturbed the sorting of a subset of both soluble and integral membrane proteins at the trans-Golgi network (TGN). We suggest that ADF/cofilin-dependent actin trimming generates a sorting domain at the TGN, which filters secretory cargo for export, and that uncontrolled growth of this domain causes missorting of proteins. This type of actin-dependent compartmentalization and filtering of secretory cargo at the TGN by ADF/cofilin could explain sorting of proteins that are destined to the cell surface.
authors.affiliation: Department of Cell and Developmental Biology, Centre de Regulació Genòmica, Barcelona, Spain.
authors.forename: Julia
authors.initials: J
authors.lastname: von Blume
authors.forename: Juan M
authors.initials: JM
authors.lastname: Duran
authors.forename: Elena
authors.initials: E
authors.lastname: Forlanelli
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Alleaume
authors.forename: Mikhail
authors.initials: M
authors.lastname: Egorov
authors.forename: Roman
authors.initials: R
authors.lastname: Polishchuk
authors.forename: Henrik
authors.initials: H
authors.lastname: Molina
authors.forename: Vivek
authors.initials: V
authors.lastname: Malhotra
mesh_terms: D051339:Actin Depolymerizing Factors / Q000235:genetics / Q000502:physiology*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D029721:Drosophila Proteins / Q000378:metabolism / Q000502:physiology; D004331:Drosophila melanogaster / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism / Q000502:physiology; D010766:Phosphorylation; D021381:Protein Transport; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D029721:Drosophila Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; C097180:tsr protein, Drosophila