Protein metabolism is highly regulated in physiological and pathophysiological states such as diabetes, starvation, etc. Both within the whole organism and at the cellular level, proteins exist in a dynamic state, maintained by the relative balance of protein synthesis and degradation. The bulk of cellular protein degradation is via the ubiquitin proteolytic pathway which provides both selectivity and specificity. Herein, cellular proteins via their internal lysine residues are tagged with ubiquitin and degraded via the proteasome. Recent evidence demonstrates (1) that this pathway exists within the cell nucleus and (2) a new pathway whereby ubiquitination is targeted to the N-terminus of a target protein. Our overall hypothesis is that cellular protein degradation is regulated in part by its loci of activity within the cell and by distinct recognition mechanisms.
The aims of the present proposal are thus (1) to analyze the motif, identify the ubiquitin ligase(s), and determine the physiological significance of N-terminus dependent ubiquitination of cellular proteins;(2) to define the subcellular site and mechanism(s) responsible for degradation of several interacting muscle development/differentiation factors;and (3) to determine the site and mechanism(s) of glucocorticoids in the accelerated protein catabolism in muscle. These studies will be carried out using a variety of physiological, pharmacological, biochemical, molecular and cellular systems. Ultimately, the ability to modulate protein metabolism in physiological and pathophysiological states requires a detailed mechanistic understanding of the pathways of protein metabolism, the subject of the present proposal.

Public Health Relevance

Protein metabolism is highly regulated in both health and disease states, such as diabetes, starvation, etc. The ability to modulate this complex process requires a detailed mechanistic understanding as described in this proposal. Our studies on the regulation of protein metabolism will provide significant insights for development of therapeutic strategies.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM067620-08
Application #
8072618
Study Section
Special Emphasis Panel (ZRG1-EMNR-B (02))
Program Officer
Somers, Scott D
Project Start
2003-06-01
Project End
2014-05-31
Budget Start
2011-06-01
Budget End
2014-05-31
Support Year
8
Fiscal Year
2011
Total Cost
$327,745
Indirect Cost
Name
Washington University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Thomas, Jane J; Abed, Mona; Heuberger, Julian et al. (2016) RNF4-Dependent Oncogene Activation by Protein Stabilization. Cell Rep 16:3388-3400
Trausch-Azar, Julie S; Abed, Mona; Orian, Amir et al. (2015) Isoform-specific SCF(Fbw7) ubiquitination mediates differential regulation of PGC-1?. J Cell Physiol 230:842-52
Trausch-Azar, Julie; Leone, Teresa C; Kelly, Daniel P et al. (2010) Ubiquitin proteasome-dependent degradation of the transcriptional coactivator PGC-1{alpha} via the N-terminal pathway. J Biol Chem 285:40192-200
Ben-Saadon, Ronen; Fajerman, Ifat; Ziv, Tamar et al. (2004) The tumor suppressor protein p16(INK4a) and the human papillomavirus oncoprotein-58 E7 are naturally occurring lysine-less proteins that are degraded by the ubiquitin system. Direct evidence for ubiquitination at the N-terminal residue. J Biol Chem 279:41414-21