Quantitative proteome analysis of the 20S proteasome of apoptotic Jurkat T cells.
Regulated proteolysis plays important roles in cell biology and pathological conditions. A crosstalk exists between apoptosis and the ubiquitin-proteasome system, two pathways responsible for regulated proteolysis executed by different proteases. To investigate whether the apoptotic process also affects the 20S proteasome, we performed three independent SILAC-based quantitative proteome approaches: 1-DE/MALDI-MS, small 2-DE/MALDI-MS and large 2-DE/nano-LC-ESI-MS. Taking the results of all experiments together, no quantitative changes were observed for the α- and β-subunits of the 20S proteasome except for subunit α7. This protein was identified in two protein spots with a down-regulation of the more acidic protein species (α7a) and up-regulation of the more basic protein species (α7b) during apoptosis. The difference in these two α7 protein species could be attributed to oxidation of cysteine-41 to cysteine sulfonic acid and phosphorylation at serine-250 near the C terminus in α7a, whereas these modifications were missing in α7b. These results pointed to the biological significance of posttranslational modifications of proteasome subunit α7 after induction of apoptosis.
Schmidt
Frank
F
The Biotechnology Centre of Oslo, University of Oslo, Gaustadalleen 21, Blindern, P.O. Box 1125, 0317, Oslo, Norway.
Dahlmann
Burkhardt
B
Hustoft
Hanne K
HK
Koehler
Christian J
CJ
Strozynski
Margarita
M
Kloss
Alexander
A
Zimny-Arndt
Ursula
U
Jungblut
Peter R
PR
Thiede
Bernd
B
D000595:Amino Acid Sequence; D017209:Apoptosis; D002853:Chromatography, Liquid / Q000379:methods; D006801:Humans; D007553:Isotope Labeling; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D008970:Molecular Weight; D036103:Nanotechnology / Q000379:methods; D009842:Oligopeptides / Q000737:chemistry; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits / Q000378:metabolism; D020543:Proteome / Q000737:chemistry / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry; D057825:Two-Dimensional Difference Gel Electrophoresis / Q000379:methods
D009842:Oligopeptides; D021122:Protein Subunits; D020543:Proteome; D046988:Proteasome Endopeptidase Complex