Protein synthesis elongation factor EF-1α is essential for ubiquitin- dependent degradation of certain N(α)-acetylated proteins and may be substituted for by the bacterial elongation factor EF-Tu

H. Gonen, C. E. Smith, N. R. Siegel, C. Kahana, W. C. Merrick, K. Chakraburtty, A. L. Schwartz, Aaron Ciechanover

Research output: Contribution to journalArticleResearchpeer-review

139 Citations (Scopus)

Abstract

Targeting of different cellular proteins for conjugation and subsequent degradation via the ubiquitin pathway involves diverse recognition signals and distinct enzymatic factors. A few proteins are recognized via their N- terminal amino acid residue and conjugated by a ubiquitin-protein ligase that recognizes this residue. Most substrates, including the N(α)-acetylated proteins that constitute the vast majority of cellular proteins, are targeted by different signals and are recognized by yet unknown ligases. We have previously shown that degradation of N-terminally blocked proteins requires a specific factor, designated FH, and that the factor acts along with the 26S protease complex to degrade ubiquitin-conjugated proteins. Here, we demonstrate that FH is the protein synthesis elongation factor EF-1α. (a) Partial sequence analysis reveals 100% identity to EF-1α. (b) Like EF-1α, FH binds to immobilized GTP (or GDP) and can be purified in one step using the corresponding nucleotide for elution. (c) Guanine nucleotides that bind to EF-1α protect the ubiquitin system-related activity of FH from heat inactivation, and nucleotides that do not bind do not exert this effect. (d) EF-Tu, the homologous bacterial elongation factor, can substitute for FH/EF- 1α in the proteolytic system. This last finding is of particular interest since the ubiquitin system has not been identified in prokaryotes. The activities of both EF-1α and EF-Tu are strongly and specifically inhibited by ubiquitin-aldehyde, a specific inhibitor of ubiquitin isopeptidases. It appears, therefore, that EF-1α may be involved in releasing ubiquitin from multiubiquitin chains, thus rendering the conjugates susceptible to the action of the 26S protease complex.

Original languageEnglish
Pages (from-to)7648-7652
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume91
Issue number16
DOIs
StatePublished - 10 Aug 1994

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Peptide Elongation Factor Tu
Peptide Elongation Factor 1
Ubiquitin
Proteins
Nucleotides
Peptide Elongation Factors
Ubiquitin-Protein Ligases
Guanine Nucleotides
Ligases
Guanosine Triphosphate
Sequence Analysis
Hot Temperature
Amino Acids

Keywords

  • N-terminally blocked proteins
  • proteolysis

Cite this

@article{0a5242bffdee44d48bc0e06683ce5248,
title = "Protein synthesis elongation factor EF-1α is essential for ubiquitin- dependent degradation of certain N(α)-acetylated proteins and may be substituted for by the bacterial elongation factor EF-Tu",
abstract = "Targeting of different cellular proteins for conjugation and subsequent degradation via the ubiquitin pathway involves diverse recognition signals and distinct enzymatic factors. A few proteins are recognized via their N- terminal amino acid residue and conjugated by a ubiquitin-protein ligase that recognizes this residue. Most substrates, including the N(α)-acetylated proteins that constitute the vast majority of cellular proteins, are targeted by different signals and are recognized by yet unknown ligases. We have previously shown that degradation of N-terminally blocked proteins requires a specific factor, designated FH, and that the factor acts along with the 26S protease complex to degrade ubiquitin-conjugated proteins. Here, we demonstrate that FH is the protein synthesis elongation factor EF-1α. (a) Partial sequence analysis reveals 100{\%} identity to EF-1α. (b) Like EF-1α, FH binds to immobilized GTP (or GDP) and can be purified in one step using the corresponding nucleotide for elution. (c) Guanine nucleotides that bind to EF-1α protect the ubiquitin system-related activity of FH from heat inactivation, and nucleotides that do not bind do not exert this effect. (d) EF-Tu, the homologous bacterial elongation factor, can substitute for FH/EF- 1α in the proteolytic system. This last finding is of particular interest since the ubiquitin system has not been identified in prokaryotes. The activities of both EF-1α and EF-Tu are strongly and specifically inhibited by ubiquitin-aldehyde, a specific inhibitor of ubiquitin isopeptidases. It appears, therefore, that EF-1α may be involved in releasing ubiquitin from multiubiquitin chains, thus rendering the conjugates susceptible to the action of the 26S protease complex.",
keywords = "N-terminally blocked proteins, proteolysis",
author = "H. Gonen and Smith, {C. E.} and Siegel, {N. R.} and C. Kahana and Merrick, {W. C.} and K. Chakraburtty and Schwartz, {A. L.} and Aaron Ciechanover",
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Protein synthesis elongation factor EF-1α is essential for ubiquitin- dependent degradation of certain N(α)-acetylated proteins and may be substituted for by the bacterial elongation factor EF-Tu. / Gonen, H.; Smith, C. E.; Siegel, N. R.; Kahana, C.; Merrick, W. C.; Chakraburtty, K.; Schwartz, A. L.; Ciechanover, Aaron.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 91, No. 16, 10.08.1994, p. 7648-7652.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Protein synthesis elongation factor EF-1α is essential for ubiquitin- dependent degradation of certain N(α)-acetylated proteins and may be substituted for by the bacterial elongation factor EF-Tu

AU - Gonen, H.

AU - Smith, C. E.

AU - Siegel, N. R.

AU - Kahana, C.

AU - Merrick, W. C.

AU - Chakraburtty, K.

AU - Schwartz, A. L.

AU - Ciechanover, Aaron

PY - 1994/8/10

Y1 - 1994/8/10

N2 - Targeting of different cellular proteins for conjugation and subsequent degradation via the ubiquitin pathway involves diverse recognition signals and distinct enzymatic factors. A few proteins are recognized via their N- terminal amino acid residue and conjugated by a ubiquitin-protein ligase that recognizes this residue. Most substrates, including the N(α)-acetylated proteins that constitute the vast majority of cellular proteins, are targeted by different signals and are recognized by yet unknown ligases. We have previously shown that degradation of N-terminally blocked proteins requires a specific factor, designated FH, and that the factor acts along with the 26S protease complex to degrade ubiquitin-conjugated proteins. Here, we demonstrate that FH is the protein synthesis elongation factor EF-1α. (a) Partial sequence analysis reveals 100% identity to EF-1α. (b) Like EF-1α, FH binds to immobilized GTP (or GDP) and can be purified in one step using the corresponding nucleotide for elution. (c) Guanine nucleotides that bind to EF-1α protect the ubiquitin system-related activity of FH from heat inactivation, and nucleotides that do not bind do not exert this effect. (d) EF-Tu, the homologous bacterial elongation factor, can substitute for FH/EF- 1α in the proteolytic system. This last finding is of particular interest since the ubiquitin system has not been identified in prokaryotes. The activities of both EF-1α and EF-Tu are strongly and specifically inhibited by ubiquitin-aldehyde, a specific inhibitor of ubiquitin isopeptidases. It appears, therefore, that EF-1α may be involved in releasing ubiquitin from multiubiquitin chains, thus rendering the conjugates susceptible to the action of the 26S protease complex.

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