Application). The manifestations of aging result in part from cells becoming less efficient at self-repair with time. These reactions represent one part of the battle of organisms to maintain the structural integrity of essential macromolecules in the face of the molecules intrinsic instabilities. Defects in these mechanisms may underlie pathologies where the aging process can be accelerated. The objective of this work is to understand how aging organisms prevent the accumulation of covalently altered proteins that can compromise cellular functions. These investigators will characterize the role of the protein L-isoaspartate (D-aspartate) O-methyltransferase that recognizes spontaneously-damaged proteins and catalyzes the initial step of a protein repair reaction. The discovery of this pathway reveals that macromolecular repair may not be just for DNA, but for proteins as well. These investigators propose to ask how the potential accumulation of damaged proteins in aging is reduced by methylation and other pathways in viva. They will utilize model organisms including bacteria, yeast, worms, and plants. Specifically, we will characterize protein damage in the bacterium Escherichia coli. They will study mutant phenotypes of both the methyltransferase pcm gene and the sure gene shown to be present in an operon with pcm. They will also study the role of associated enzymes that are involved in the metabolism of isoaspartyl-containing proteins and peptides, including isoaspartyl dipeptidases. They will analyze mutants of the protein repair methyltransferase in the nematode worm Casnorhabditis elegant. They will ask how the yeast Saccharomyces cerevisiae can avoid the accumulation of proteins containing altered aspartyl residues in spite of the fact that it naturally lacks the methyltransferase. Finally, they will examine the role of the methylation reaction in controlling protein damage in higher plants, including corn and Arabidopsis. These studies will hopefully not only provide a new window to view protein life but may also suggest that the biological aging process may be closely linked to how well cells can keep polypeptides free of spontaneous covalent damage.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
1R01AG018000-01
Application #
6093306
Study Section
Special Emphasis Panel (ZAG1-PKN-8 (J1))
Program Officer
Bellino, Francis
Project Start
2000-06-15
Project End
2004-05-30
Budget Start
2000-06-15
Budget End
2001-05-30
Support Year
1
Fiscal Year
2000
Total Cost
$225,909
Indirect Cost
Name
University of California Los Angeles
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Vinci, Chris R; Clarke, Steven G (2010) Yeast, plants, worms, and flies use a methyltransferase to metabolize age-damaged (R,S)-AdoMet, but what do mammals do? Rejuvenation Res 13:362-4
Khare, Shilpi; Gomez, Tara; Linster, Carole L et al. (2009) Defective responses to oxidative stress in protein l-isoaspartyl repair-deficient Caenorhabditis elegans. Mech Ageing Dev 130:670-80
Banfield, Kelley L; Gomez, Tara A; Lee, Wendy et al. (2008) Protein-repair and hormone-signaling pathways specify dauer and adult longevity and dauer development in Caenorhabditis elegans. J Gerontol A Biol Sci Med Sci 63:798-808
Linster, Carole L; Adler, Lital N; Webb, Kristofor et al. (2008) A second GDP-L-galactose phosphorylase in arabidopsis en route to vitamin C. Covalent intermediate and substrate requirements for the conserved reaction. J Biol Chem 283:18483-92
Gomez, Tara A; Banfield, Kelley L; Clarke, Steven G (2008) The protein L-isoaspartyl-O-methyltransferase functions in the Caenorhabditis elegans stress response. Mech Ageing Dev 129:752-8
Linster, Carole L; Clarke, Steven G (2008) L-Ascorbate biosynthesis in higher plants: the role of VTC2. Trends Plant Sci 13:567-73
Gomez, Tara A; Banfield, Kelley L; Trogler, Dorothy M et al. (2007) The L-isoaspartyl-O-methyltransferase in Caenorhabditis elegans larval longevity and autophagy. Dev Biol 303:493-500
Vinci, Chris R; Clarke, Steven G (2007) Recognition of age-damaged (R,S)-adenosyl-L-methionine by two methyltransferases in the yeast Saccharomyces cerevisiae. J Biol Chem 282:8604-12
Gomez, Tara A; Clarke, Steven G (2007) Autophagy and insulin/TOR signaling in Caenorhabditis elegans pcm-1 protein repair mutants. Autophagy 3:357-9
Yang, Mei-Ling; Doyle, Hester A; Gee, Renelle J et al. (2006) Intracellular protein modification associated with altered T cell functions in autoimmunity. J Immunol 177:4541-9

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