Mass spectrometric characterization of the affinity-purified human 26S proteasome complex.
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Wang X, Chen CF, Baker PR, Chen PL, Kaiser P, Huang L
Mass spectrometric characterization of the affinity-purified human 26S proteasome complex.
Biochemistry. 2007 Mar 20;46(11):3553-65. Epub 2007 Feb 27.
- PubMed ID
- 17323924 [ View in PubMed]
- Abstract
The 26S proteasome is a multisubunit complex responsible for degradation of ubiquitinated substrates, which plays a critical role in regulating various biological processes. To fully understand the function and regulation of the proteasome complex, an important step is to elucidate its subunit composition and posttranslational modifications. Toward this goal, a new affinity purification strategy has been developed using a derivative of the HB tag for rapid isolation of the human 26S proteasome complex for subsequent proteomic analysis. The purification of the complex is achieved from stable 293 cell lines expressing a HB-tagged proteasome subunit and by high-affinity streptavidin binding with TEV cleavage elution. The complete composition of the 26S proteasome complex, including recently assigned new subunits, is identified by LC-MS/MS. In addition, all known proteasome activator proteins and components involved in the ubiquitin-proteasome degradation pathway are identified. Aside from the subunit composition, the N-terminal modification and phosphorylation of the proteasome subunits have been characterized. Twelve novel phosphorylation sites from eight subunits have been identified, and N-terminal modifications are determined for 25 subunits, 12 of which have not been previously reported in mammals. We also observe different N-terminal processing of subunit Rpn2, which results in identification of two different N-termini of the protein. This work presents the first comprehensive characterization of the human 26S proteasome complex by affinity purification and tandem mass spectrometry. The detailed proteomic profiling obtained here is significant to future studies aiming at a complete understanding of the structure-function relationship of the human 26S proteasome complex.
DrugBank Data that Cites this Article
- Polypeptides
Name UniProt ID Proteasome subunit beta type-1 P20618 Details Proteasome subunit beta type-5 P28074 Details Proteasome subunit beta type-2 P49721 Details Proteasome subunit alpha type-1 P25786 Details Proteasome subunit alpha type-2 P25787 Details Proteasome subunit alpha type-3 P25788 Details Proteasome subunit alpha type-4 P25789 Details Proteasome subunit alpha type-5 P28066 Details Proteasome subunit alpha type-6 P60900 Details Proteasome subunit alpha type-7 O14818 Details Proteasome subunit beta type-3 P49720 Details Proteasome subunit beta type-4 P28070 Details Proteasome subunit beta type-6 P28072 Details Proteasome subunit beta type-7 Q99436 Details Proteasome activator complex subunit 1 Q06323 Details 26S protease regulatory subunit 6A P17980 Details