title: Integral and associated lysosomal membrane proteins.
abstract: We searched for novel proteins in lysosomal membranes, tentatively participating in molecular transport across the membrane and/or in interactions with other compartments. In membranes purified from placental lysosomes, we identified 58 proteins, known to reside at least partially in the lysosomal membrane. These included 17 polypeptides comprising or associated with the vacuolar adenosine triphosphatase. We report on additional 86 proteins that were significantly enriched in the lysosomal membrane fraction. Among these, 12 novel proteins of unknown functions were found. Three were orthologues of rat proteins that have been identified in tritosomes by Bagshaw RD et al. (A proteomic analysis of lysosomal integral membrane proteins reveals the diverse composition of the organelle. Mol Cell Proteomics 2005;4:133-143). Here, the proteins encoded by LOC201931 (FLJ38482) and LOC51622 (C7orf28A) were expressed with an appended fluorescent tag in HeLa cells and found to be present in lysosomal organelles. Among the lysosomally enriched proteins, also 16 enzymes and transporters were detected that had not been assigned to lysosomal membranes previously. Finally, our results identified a particular set of proteins with known functions in signaling and targeting to be at least partially associated with lysosomes.
authors: Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
authors: Bernd
authors: B
authors: Schröder
authors: Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
authors: Christian
authors: C
authors: Wrocklage
authors: Department of Proteomics and Signal Transduction, Max-Planck-Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors: Cuiping
authors: C
authors: Pan
authors: Institute of Medical Biometry and Epidemiology, Philipps-University Marburg, Bunsenstraße 3, 35032 Marburg, Germany.
authors: Ralf
authors: R
authors: Jäger
authors: Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
authors: Bernd
authors: B
authors: Kösters
authors: Institute of Medical Biometry and Epidemiology, Philipps-University Marburg, Bunsenstraße 3, 35032 Marburg, Germany.
authors: Helmut
authors: H
authors: Schäfer
authors: Institute of Cytobiology and Cytopathology, Philipps-University Marburg, Robert-Koch-Straße 6, 35032 Marburg, Germany.
authors: Hans-Peter
authors: HP
authors: Elsässer
authors: Department of Proteomics and Signal Transduction, Max-Planck-Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors: Matthias
authors: M
authors: Mann
authors: Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
authors: Andrej
authors: A
authors: Hasilik
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods; D008854:Microscopy, Electron; D008954:Models, Biological; D010920:Placenta / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D015398:Signal Transduction
chemical_list: D011993:Recombinant Fusion Proteins; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases