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Structure of the human 26S proteasome bound to USP14-UbAl
Structural highlights
FunctionPSA7_HUMAN The proteasome is a multicatalytic proteinase complex which is characterized by its ability to cleave peptides with Arg, Phe, Tyr, Leu, and Glu adjacent to the leaving group at neutral or slightly basic pH. The proteasome has an ATP-dependent proteolytic activity. Plays an important role in the regulation of cell proliferation or cell cycle control, transcriptional regulation, immune and stress response, cell differentiation, and apoptosis. Interacts with some important proteins involved in transcription factor regulation, cell cycle transition, viral replication and even tumor initiation and progression. Inhibits the transactivation function of HIF-1A under both normoxic and hypoxia-mimicking conditions. The interaction with EMAP2 increases the proteasome-mediated HIF-1A degradation under the hypoxic conditions. Plays a role in hepatitis C virus internal ribosome entry site-mediated translation. Mediates nuclear translocation of the androgen receptor (AR) and thereby enhances androgen-mediated transactivation. Promotes MAVS degradation and thereby negatively regulates MAVS-mediated innate immune response.[1] [2] [3] [4] [5] Publication Abstract from PubMedWe report the cryo-EM structure of the human 26S proteasome at an average resolution of 3.5 A, allowing atomic modeling of 28 subunits in the core particle (CP) and 18 subunits in the regulatory particle (RP). The C-terminal residues of Rpt3 and Rpt5 subunits in the RP can be seen inserted into surface pockets formed between adjacent alpha subunits in the CP. Each of the six Rpt subunits contains a bound nucleotide, and the central gate of the CP alpha-ring is closed despite RP association. The six pore 1 loops in the Rpt ring are arranged similarly to a spiral staircase along the axial channel of substrate transport, which is constricted by the pore 2 loops. We also determined the cryo-EM structure of the human proteasome bound to the deubiquitinating enzyme USP14 at 4.35-A resolution. Together, our structures provide a framework for mechanistic understanding of eukaryotic proteasome function. An atomic structure of the human 26S proteasome.,Huang X, Luan B, Wu J, Shi Y Nat Struct Mol Biol. 2016 Jul 18. doi: 10.1038/nsmb.3273. PMID:27428775[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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