title: Proteomics fingerprinting of phagosome maturation and evidence for the role of a Galpha during uptake.
abstract: Phagocytosis, whether of food particles in protozoa or bacteria and cell remnants in the metazoan immune system, is a conserved process. The particles are taken up into phagosomes, which then undergo complex remodeling of their components, called maturation. By using two-dimensional gel electrophoresis and mass spectrometry combined with genomic data, we identified 179 phagosomal proteins in the amoeba Dictyostelium, including components of signal transduction, membrane traffic, and the cytoskeleton. By carrying out this proteomics analysis over the course of maturation, we obtained time profiles for 1,388 spots and thus generated a dynamic record of phagosomal protein composition. Clustering of the time profiles revealed five clusters and 24 functional groups that were mapped onto a flow chart of maturation. Two heterotrimeric G protein subunits, Galpha4 and Gbeta, appeared at the earliest times. We showed that mutations in the genes encoding these two proteins produce a phagocytic uptake defect in Dictyostelium. This analysis of phagosome protein dynamics provides a reference point for future genetic and functional investigations.
authors.affiliation: Department of Molecular Cell Research, Max Planck Institute for Medical Research, University Hospital of Heidelberg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gotthardt
authors.forename: Vincent
authors.initials: V
authors.lastname: Blancheteau
authors.forename: Armin
authors.initials: A
authors.lastname: Bosserhoff
authors.forename: Thomas
authors.initials: T
authors.lastname: Ruppert
authors.forename: Mauro
authors.initials: M
authors.lastname: Delorenzi
authors.forename: Thierry
authors.initials: T
authors.lastname: Soldati
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002478:Cells, Cultured; D016000:Cluster Analysis; D004023:Dictyostelium; D015180:Electrophoresis, Gel, Two-Dimensional; D044385:GTP-Binding Protein alpha Subunits / Q000502:physiology*; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics; D008954:Models, Biological; D010587:Phagocytosis; D010588:Phagosomes / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*
chemical_list: D044385:GTP-Binding Protein alpha Subunits; D044387:GTP-Binding Protein beta Subunits