[Seminar] Cryo-EM of fully recombinant human proteasomes – a new approach with new potential applications
Ana Toste Rego
| When |
19 Dec, 2019
from
02:30 pm to 03:30 pm |
|---|---|
| Where | 2.13 |
| Contact Name | Pedro Matias |
| Contact Email | matias@itqb.unl.pt |
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Title: Cryo-EM of fully recombinant human proteasomes – a new approach with new potential applications
Speaker: Ana Toste Rego
Affiliation: Research Officer at MRC-LMB, Cambridge, UK
Abstract:
The 20S proteasome is the catalytical core of the 26S proteasome, a key player in the ubiquitin proteasome pathway (UPS). Because the proteasome is involved in many key cellular processes, it is a very well established drug target. Despite that, our understanding of its mechanisms of function and regulation is still significantly elusive. The major limitations in studying the human proteasome are its structural complexity, its physiological variants, the limited availability of purified homogeneous complexes and the impairment of relevant mutational studies due to lethality. These limitations could be overcome with the preparation of recombinant complexes, which has so far been unsuccessful. This can be due to the complexity of the human 20S proteasome assembly pathway, which requires the expression and chaperone assisted step‑assembly of two copies of 14 closely related subunits, α1-7 and β1-7.
Here we show an effective approach for the preparation of recombinant human proteasomes and demonstrate the structural and functional integrity of the recombinant complexes. For this purpose, we solved the cryo-EM structure of the recombinant human 20S proteasome in the apo form (at 2.6 Å resolution) and in complex with PA200 (at 3 Å resolution), a still poorly characterised proteasome activator involved in acetylation dependent histone degradation. These structures reveal new insights into the PA200 function and the proteasome activity allosteric modulation, which has so far been elusive. We have now the tools to further characterise proteasome variants and unveil many proteasome mechanistic aspects that have remained obscure. We also provide an important new tool for the design and development of novel therapeutic drugs.
Bio:
