Polyubiquitin (polyUb) chains linked through Ub-K63 act as a non-proteolytic signal in the conserved RAD6 DNA damage tolerance pathway, while chains linked through Ub-K48 play a different role, acting as a signal for proteasome proteolysis. These and other observations suggest that the assembly of Ub into different types of polyUb chains is a mechanism for imparting functional diversity in signaling by ubiquitin. Signaling by K63-1inked polyUb chains in DNA damage tolerance is conserved from yeast to man. But despite recent advances, the molecular function of this novel signal remains poorly understood. The proposed research targets this question through mechanistically focused approaches involving biochemical and molecular genetic methods. The specific goals are 1) to elucidate the specific mechanism of DNA damage signaling by K63-1inked polyUb chains (Aims 1-3) and 2) to discover the principles that underlie linkage-specific chain recognition by a small Ub-binding element that occurs in numerous proteins (the UBA domain;
Aim 4). The results of our studies may shed light on the causes of cancer and other diseases promoted by genomic instability. Our findings may also suggest ways to inhibit the RAD6 pathway, which could be clinically beneficial in chemotherapy or radiosensitization. Finally, our molecular exploration of (poly)Ub recognition by UBA domains should help to establish fundamental signal recognition principles and may lead to a better appreciation of diversity and specificity in signaling by ubiquitin.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM060372-05
Application #
6782779
Study Section
Biochemistry Study Section (BIO)
Program Officer
Wolfe, Paul B
Project Start
2000-02-01
Project End
2008-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
5
Fiscal Year
2004
Total Cost
$343,350
Indirect Cost
Name
Johns Hopkins University
Department
Biochemistry
Type
Schools of Public Health
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Carlile, Candice M; Pickart, Cecile M; Matunis, Michael J et al. (2009) Synthesis of free and proliferating cell nuclear antigen-bound polyubiquitin chains by the RING E3 ubiquitin ligase Rad5. J Biol Chem 284:29326-34
Zhang, Daoning; Raasi, Shahri; Fushman, David (2008) Affinity makes the difference: nonselective interaction of the UBA domain of Ubiquilin-1 with monomeric ubiquitin and polyubiquitin chains. J Mol Biol 377:162-80
Eddins, Michael J; Carlile, Candice M; Gomez, Kamila M et al. (2006) Mms2-Ubc13 covalently bound to ubiquitin reveals the structural basis of linkage-specific polyubiquitin chain formation. Nat Struct Mol Biol 13:915-20
Raasi, Shahri; Varadan, Ranjani; Fushman, David et al. (2005) Diverse polyubiquitin interaction properties of ubiquitin-associated domains. Nat Struct Mol Biol 12:708-14
Varadan, Ranjani; Assfalg, Michael; Raasi, Shahri et al. (2005) Structural determinants for selective recognition of a Lys48-linked polyubiquitin chain by a UBA domain. Mol Cell 18:687-98
Tsui, Colleen; Raguraj, Arani; Pickart, Cecile M (2005) Ubiquitin binding site of the ubiquitin E2 variant (UEV) protein Mms2 is required for DNA damage tolerance in the yeast RAD6 pathway. J Biol Chem 280:19829-35
Pickart, Cecile M (2004) Back to the future with ubiquitin. Cell 116:181-90
Pickart, Cecile M; Eddins, Michael J (2004) Ubiquitin: structures, functions, mechanisms. Biochim Biophys Acta 1695:55-72
Varadan, Ranjani; Assfalg, Michael; Haririnia, Aydin et al. (2004) Solution conformation of Lys63-linked di-ubiquitin chain provides clues to functional diversity of polyubiquitin signaling. J Biol Chem 279:7055-63
Wu, Pei-Ying; Hanlon, Mary; Eddins, Michael et al. (2003) A conserved catalytic residue in the ubiquitin-conjugating enzyme family. EMBO J 22:5241-50

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