Integral and associated lysosomal membrane proteins.
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.
Schröder
Bernd
B
Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
Wrocklage
Christian
C
Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
Pan
Cuiping
C
Department of Proteomics and Signal Transduction, Max-Planck-Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
Jäger
Ralf
R
Institute of Medical Biometry and Epidemiology, Philipps-University Marburg, Bunsenstraße 3, 35032 Marburg, Germany.
Kösters
Bernd
B
Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
Schäfer
Helmut
H
Institute of Medical Biometry and Epidemiology, Philipps-University Marburg, Bunsenstraße 3, 35032 Marburg, Germany.
Elsässer
Hans-Peter
HP
Institute of Cytobiology and Cytopathology, Philipps-University Marburg, Robert-Koch-Straße 6, 35032 Marburg, Germany.
Mann
Matthias
M
Department of Proteomics and Signal Transduction, Max-Planck-Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
Hasilik
Andrej
A
Institute of Physiological Chemistry, Philipps-University Marburg, Karl-von-Frisch-Straße 1, 35032 Marburg, Germany.
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
D011993:Recombinant Fusion Proteins; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases