Tripartite degrons confer diversity and specificity on regulated protein degradation in the ubiquitin-proteasome system.

TitleTripartite degrons confer diversity and specificity on regulated protein degradation in the ubiquitin-proteasome system.
Publication TypeJournal Article
Year of Publication2016
AuthorsGuharoy, M., Bhowmick P., Sallam M., and Tompa P.
JournalNat Commun
Volume7
Pagination10239
Date Published2016 Jan 06
ISSN2041-1723
KeywordsAnimals, Gene Expression Regulation, Humans, Mammals, Models, Molecular, Proteasome Endopeptidase Complex, Protein Conformation, Proteins, Proteolysis, Ubiquitins
Abstract

Specific signals (degrons) regulate protein turnover mediated by the ubiquitin-proteasome system. Here we systematically analyse known degrons and propose a tripartite model comprising the following: (1) a primary degron (peptide motif) that specifies substrate recognition by cognate E3 ubiquitin ligases, (2) secondary site(s) comprising a single or multiple neighbouring ubiquitinated lysine(s) and (3) a structurally disordered segment that initiates substrate unfolding at the 26S proteasome. Primary degron sequences are conserved among orthologues and occur in structurally disordered regions that undergo E3-induced folding-on-binding. Posttranslational modifications can switch primary degrons into E3-binding-competent states, thereby integrating degradation with signalling pathways. Degradation-linked lysines tend to be located within disordered segments that also initiate substrate degradation by effective proteasomal engagement. Many characterized mutations and alternative isoforms with abrogated degron components are implicated in disease. These effects result from increased protein stability and interactome rewiring. The distributed nature of degrons ensures regulation, specificity and combinatorial control of degradation.

DOI10.1038/ncomms10239
Alternate JournalNat Commun
PubMed ID26732515
PubMed Central IDPMC4729826
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