Structure 2012-03-07

The UBAP1 subunit of ESCRT-I interacts with ubiquitin via a SOUBA domain.

Monica Agromayor, Nicolas Soler, Anna Caballe, Tonya Kueck, Stefan M Freund, Mark D Allen, Mark Bycroft, Olga Perisic, Yu Ye, Bethan McDonald, Hartmut Scheel, Kay Hofmann, Stuart J D Neil, Juan Martin-Serrano, Roger L Williams

文献索引：Structure 20 , 414-28, (2012)

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摘要

The endosomal sorting complexes required for transport (ESCRTs) facilitate endosomal sorting of ubiquitinated cargo, MVB biogenesis, late stages of cytokinesis, and retroviral budding. Here we show that ubiquitin associated protein 1 (UBAP1), a subunit of human ESCRT-I, coassembles in a stable 1:1:1:1 complex with Vps23/TSG101, VPS28, and VPS37. The X-ray crystal structure of the C-terminal region of UBAP1 reveals a domain that we describe as a solenoid of overlapping UBAs (SOUBA). NMR analysis shows that each of the three rigidly arranged overlapping UBAs making up the SOUBA interact with ubiquitin. We demonstrate that UBAP1-containing ESCRT-I is essential for degradation of antiviral cell-surface proteins, such as tetherin (BST-2/CD317), by viral countermeasures, namely, the HIV-1 accessory protein Vpu and the Kaposi sarcoma-associated herpesvirus (KSHV) ubiquitin ligase K5.Copyright © 2012 Elsevier Ltd. All rights reserved.