Cited by 544Ubiquitin and proteasome pathwaysProtein Degradation and InhibitorsAutophagy in Disease and Therapy

N-degron and C-degron pathways of protein degradation

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Varshavsky, Alexander·2019·Proceedings of the National Academy of Sciences

Abstract

This perspective is partly review and partly proposal. N-degrons and C-degrons are degradation signals whose main determinants are, respectively, the N-terminal and C-terminal residues of cellular proteins. N-degrons and C-degrons include, to varying extents, adjoining sequence motifs, and also internal lysine residues that function as polyubiquitylation sites. Discovered in 1986, N-degrons were the first degradation signals in short-lived proteins. A particularly large set of C-degrons was discovered in 2018. We describe multifunctional proteolytic systems that target N-degrons and C-degrons. We also propose to denote these systems as “N-degron pathways” and “C-degron pathways.” The former notation replaces the earlier name “N-end rule pathways.” The term “N-end rule” was introduced 33 years ago, when only some N-terminal residues were thought to be destabilizing. However, studies over the last three decades have shown that all 20 amino acids of the genetic code can act, in cognate sequence contexts, as destabilizing N-terminal residues. Advantages of the proposed terms include their brevity and semantic uniformity for N-degrons and C-degrons. In addition to being topologically analogous, N-degrons and C-degrons are related functionally. A proteolytic cleavage of a subunit in a multisubunit complex can create, at the same time, an N-degron (in a C-terminal fragment) and a spatially adjacent C-degron (in an N-terminal fragment). Consequently, both fragments of a subunit can be selectively destroyed through attacks by the N-degron and C-degron pathways.

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Crossref · 10.1073/pnas.1816596116

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  • The cytosolic C-terminal E5 degron has been described to increase protein turnover and proteasomal degradation in the cytosol.

    “Additionally, MHC class I loading might be enhanced by the cytosolic, C-terminal E5 degron, which has been described to increase protein turnover and proteasomal degradation in the cytosol [30].”

    From Preclinical development of an mRNA-based multiepitope immunotherapeutic for glioblastoma (2025) · cites this paper as [30]

    The Eukaryotic C-Degron Pathways section describes C-terminal degrons as degradation signals and says that a protein whose C-degron remains exposed faces an increasing probability of destruction. It does not identify an E5 degron or establish that this specific cytosolic degron increases protein turnover and proteasomal degradation. Page numbers are unavailable in our copy. (LLM, conf=0.84)

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Authors
Varshavsky, A.
Affiliations
California Institute of Technology (US)
Corresponding author
Varshavsky, Alexander
Venue
Proceedings of the National Academy of Sciences
Published
2019-01-07
Volume
116
Issue
2
Pages
358-366
ISSN
  • 0027-8424 (ISSN-L)
  • 1091-6490
OpenAlex
W2910161842
Cited by
544
References
82
Citations by year
2026: 52 · 2025: 71 · 2024: 79 · 2023: 84 · 2022: 77 · 2021: 77 · 2020: 68 · 2019: 36
FWCI
5.66
Type
journal article
Language
en
Open access
Locations
  • Proceedings of the National Academy of Sciences (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • CaltechAUTHORS (California Institute of Technology) (submittedVersion)
Funders
HHS | National Institutes of Health (DK039520, GM031530)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Ubiquitin and proteasome pathways
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Degradation and Inhibitors
  • Health Sciences › Medicine › Epidemiology › Autophagy in Disease and Therapy
Keywords
N-degron, protein degradation, N-end rule, protein destabilization, polyubiquitination, proteolytic pathways, short-lived proteins, protein quality control
MeSH terms
Protein Domains, Amino Acid Sequence, Animals, Humans, Amino Acid Motifs, Proteolysis

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