Abstract

Ubiquitin is a 76-residue protein that exists in cells either free or conjugated to many other proteins. Selective degradation of proteins by the ubiquitin/proteasome-dependent pathways plays a role in a multitude of biological processes, including cell growth and differentiation, signal transduction and responses to stress. One ubiquitin/proteasome-dependent proteolytic system is the N-end rule pathway, identified by the laboratory in 1986. The N-end rule relates the in vivo half-life of a protein to the identity of its N-terminal residue. The N-end rule pathway is present in all organisms examined, from mammals to bacteria. Studies supported by the present grant (""""""""Mechanics and Functions of the N-end Rule Pathway"""""""", DK39520), currently in its 11th year, have yielded significant insights into the N-end rule's functions and mechanisms, as described in the Progress Report. The objective of the research described in this renewal application is to advance the understanding of the N-end rule pathway and related aspects of the ubiquitin system.
Specific aims are: 1) Regulation of peptide import by the N-end rule pathway: biochemical and genetic studies; 2) A fusion-based screen for physiological substrates of the N-end rule pathway in S. cerevisiae; 3) Isolation and analysis of regulators of the N-end rule pathway; 4) Screens for mutants whose viability requires the presence of the N-end r; 5) The use of suppression subtractive hybridization to identify new functions of the N-end rule pathway; 6) Analysis of a mitochondrial function of the Ntalp N-terminal amidase in S. cerevisiae; 7) A biochemico-genetic approach to identification of physiological N-end rule substrates; 8) A """"""""double-headed"""""""" inhibitor of the N-end rule pathway; 9) The """"""""two-ubiquitin"""""""" technique and its application to the problem of cotranslational proteolysis; and 10) Biochemical and genetic dissection of the UBRI-encoded Nrecognin and Ubr2p, a recently identified homolog of Ubrlp in S. cerevisiae.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37DK039520-21
Application #
7176060
Study Section
Special Emphasis Panel (NSS)
Program Officer
Haft, Carol R
Project Start
1995-02-11
Project End
2008-01-31
Budget Start
2007-02-01
Budget End
2008-01-31
Support Year
21
Fiscal Year
2007
Total Cost
$631,697
Indirect Cost

  Institution

Name
California Institute of Technology
Department
Type
Schools of Arts and Sciences
DUNS #
009584210
City
Pasadena
State
CA
Country
United States
Zip Code
91125

  Publications

Oh, Jang-Hyun; Hyun, Ju-Yeon; Varshavsky, Alexander (2017) Control of Hsp90 chaperone and its clients by N-terminal acetylation and the N-end rule pathway. Proc Natl Acad Sci U S A 114:E4370-E4379
Piatkov, Konstantin I; Vu, Tri T M; Hwang, Cheol-Sang et al. (2015) Formyl-methionine as a degradation signal at the N-termini of bacterial proteins. Microb Cell 2:376-393
Park, Sang-Eun; Kim, Jeong-Mok; Seok, Ok-Hee et al. (2015) Control of mammalian G protein signaling by N-terminal acetylation and the N-end rule pathway. Science 347:1249-1252
Piatkov, Konstantin I; Oh, Jang-Hyun; Liu, Yuan et al. (2014) Calpain-generated natural protein fragments as short-lived substrates of the N-end rule pathway. Proc Natl Acad Sci U S A 111:E817-26
Brower, Christopher S; Rosen, Connor E; Jones, Richard H et al. (2014) Liat1, an arginyltransferase-binding protein whose evolution among primates involved changes in the numbers of its 10-residue repeats. Proc Natl Acad Sci U S A 111:E4936-45
Kim, Heon-Ki; Kim, Ryu-Ryun; Oh, Jang-Hyun et al. (2014) The N-terminal methionine of cellular proteins as a degradation signal. Cell 156:158-69
Piatkov, Konstantin; Graciet, Emmanuelle; Varshavsky, Alexander (2013) Ubiquitin reference technique and its use in ubiquitin-lacking prokaryotes. PLoS One 8:e67952
Brower, Christopher S; Piatkov, Konstantin I; Varshavsky, Alexander (2013) Neurodegeneration-associated protein fragments as short-lived substrates of the N-end rule pathway. Mol Cell 50:161-71
Shemorry, Anna; Hwang, Cheol-Sang; Varshavsky, Alexander (2013) Control of protein quality and stoichiometries by N-terminal acetylation and the N-end rule pathway. Mol Cell 50:540-51
Varshavsky, Alexander (2012) Augmented generation of protein fragments during wakefulness as the molecular cause of sleep: a hypothesis. Protein Sci 21:1634-61

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