Eukaryotes have a highly conserved enzymatic system for the ligation of ubiquitin (Ub) to proteins. Moreover, polypeptides distinct from but related to Ub, called Ub-like proteins or Ubls, can also be attached to proteins. Ligation to each Ubl has unique mechanistic and functional consequences. SUMO (small Ub-related modifier) is a highly divergent Ubl, and the SUMO ligation system has crucial roles in many organisms, including important contributions to human biology. Both Ub and SUMO attachment to proteins can be rapidly reversed in vivo, and specialized proteases are responsible for these cleavage reactions. The PI has been analyzing the deubiquitinating enzyme (DUB) family, primarily in the yeast Saccharomyces cerevisiae, and the first SUMO-specific proteases, the ULPs, were discovered in the PI's laboratory. ULP- class proteases are essential for embryogenesis in the mouse and are overexpressed in several human cancers. Therefore these enzymes have emerged as attractive targets for drug development. The long-range objective of the project is to gain a molecular understanding of the physiological and mechanistic roles played by DUBs and ULPs in vivo. In this renewal application, the proposed experiments are concentrated on SUMO modification in yeast and on the contributions of the two yeast desumoylating enzymes, Ulp1 and Ulp2, to SUMO system function. Mutation of either ULP has strong effects on growth and division, and Ulp1, like SUMO itself, is essential for cell-cycle progression. In broad terms, the goals are two-fold: Determine the molecular basis for key regulatory functions of the Ulp1 and Ulp2 enzymes and elucidate the molecular features of these SUMO proteases that are responsible for their dramatic differences in specificity and activity. Recent data on Ulp1 and Ulp2 have directed the studies into several specific areas of biological regulation. Based on these new findings, the following Aims are proposed: (1) Examine the function of Ulp1 at the nuclear pore complex, particularly its role in pre-mRNA nuclear retention;(2) Determine novel regulatory features of Ulp2, especially its role in chromatin regulation, and determine the contributions of Ulp2 noncatalytic domains to its in vivo regulation;and (3) Examine how SUMO attachment to substrates apparently promotes their ubiquitination by the heterodimeric Hex3-Slx8 Ub ligase.

Public Health Relevance

The growth and behavior of human cells, like those of virtually all complex organisms, is controlled by rapid attachment and removal of small specialized proteins (called ubiquitin-like proteins) to and from other proteins. Defects in the enzymes that control these processes are known to cause human developmental abnormalities, neurodegenerative disorders, and many different forms of cancer. This project aims to deepen our understanding of the enzymes that detach certain ubiquitin-like proteins from their partners, with the long-term goal of developing therapies to treat patients suffering from cancer and other diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM053756-17S1
Application #
8538126
Study Section
Membrane Biology and Protein Processing (MBPP)
Program Officer
Gerratana, Barbara
Project Start
1996-03-01
Project End
2013-08-31
Budget Start
2011-03-01
Budget End
2013-08-31
Support Year
17
Fiscal Year
2012
Total Cost
$113,478
Indirect Cost
$45,023
Name
Yale University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Ryu, Hong-Yeoul; Wilson, Nicole R; Mehta, Sameet et al. (2016) Loss of the SUMO protease Ulp2 triggers a specific multichromosome aneuploidy. Genes Dev 30:1881-94
Ryu, Hong-Yeoul; Hochstrasser, Mark (2016) Adaptive aneuploidy counters a dysregulated SUMO system. Cell Cycle :1-3
Ronau, Judith A; Beckmann, John F; Hochstrasser, Mark (2016) Substrate specificity of the ubiquitin and Ubl proteases. Cell Res 26:441-56
Wilson, Nicole R; Hochstrasser, Mark (2016) The Regulation of Chromatin by Dynamic SUMO Modifications. Methods Mol Biol 1475:23-38
Gillies, Jennifer; Hickey, Christopher M; Su, Dan et al. (2016) SUMO Pathway Modulation of Regulatory Protein Binding at the Ribosomal DNA Locus in Saccharomyces cerevisiae. Genetics 202:1377-94
Hu, Ronggui; Hochstrasser, Mark (2016) Recent progress in ubiquitin and ubiquitin-like protein (Ubl) signaling. Cell Res 26:389-90
Hickey, Christopher M; Hochstrasser, Mark (2015) STUbL-mediated degradation of the transcription factor MATα2 requires degradation elements that coincide with corepressor binding sites. Mol Biol Cell 26:3401-12
Kang, Hyeran; Bradley, Michael J; Cao, Wenxiang et al. (2014) Site-specific cation release drives actin filament severing by vertebrate cofilin. Proc Natl Acad Sci U S A 111:17821-6
Hickey, Christopher M; Wilson, Nicole R; Hochstrasser, Mark (2012) Function and regulation of SUMO proteases. Nat Rev Mol Cell Biol 13:755-66
Gillies, Jennifer; Hochstrasser, Mark (2012) A new class of SUMO proteases. EMBO Rep 13:284-5

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