Multiple associated proteins regulate proteasome structure and function.

David S Leggett; John Hanna; Anna Borodovsky; Bernat Crosas; Marion Schmidt; Rohan T Baker; Thomas Walz; Hidde Ploegh; Daniel Finley

doi:10.1016/s1097-2765(02)00638-x

PubMed · 12408819

Multiple associated proteins regulate proteasome structure and function.

David S Leggett·John Hanna·Anna Borodovsky·Bernat Crosas·Marion Schmidt·Rohan T Baker·Thomas Walz·Hidde Ploegh·Daniel Finley

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Abstract

We have identified proteins that are abundant in affinity-purified proteasomes, but absent from proteasomes as previously defined because elevated salt concentrations dissociate them during purification. The major components are a deubiquitinating enzyme (Ubp6), a ubiquitin-ligase (Hul5), and an uncharacterized protein (Ecm29). Ecm29 tethers the proteasome core particle to the regulatory particle. Proteasome binding activates Ubp6 300-fold and is mediated by the ubiquitin-like domain of Ubp6, which is required for function in vivo. Ubp6 recognizes the proteasome base and its subunit Rpn1, suggesting that proteasome binding positions Ubp6 proximally to the substrate translocation channel. ubp6Delta mutants exhibit accelerated turnover of ubiquitin, indicating that deubiquitination events catalyzed by Ubp6 prevent translocation of ubiquitin into the proteolytic core particle.

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Adenosine Triphosphate Binding Sites Canavanine Cysteine Endopeptidases Endopeptidases Ligases Multienzyme Complexes Proteasome Endopeptidase Complex Protein Binding Protein Subunits Proteins Recombinant Fusion Proteins Saccharomyces cerevisiae Saccharomyces cerevisiae Proteins Salts Ubiquitin-Protein Ligases Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.

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David S Leggett, John Hanna, Anna Borodovsky, Bernat Crosas, Marion Schmidt, Rohan T Baker, Thomas Walz, Hidde Ploegh, Daniel Finley. 2002. Multiple associated proteins regulate proteasome structure and function.. https://doi.org/10.1016/s1097-2765(02)00638-x

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