74 research outputs found
FINAL REPORT: The Role of RUB (related to ubiquitin) Family of Proteins in the Hormone Response
No full textThe Rub pathway is a conserved protein modification pathway. RUB (called Rubp1 in budding yeast, Nedd8 in animals and RUB in plants) is a ubiquitin-like 76-amino acid protein. It covalently attaches to protein using an enzymatic machinery analogous to the enzymes that attach ubiquitin to its substrate proteins. However, the nature of the complement of Rub-modified proteins in organisms was not clear. From bioinformatics analyses, one can identify a Rub activating enzymes and Rub conjugating enzymes. However, in many cases, their biochemical properties were not described. In DOE-funded work, we made major advances in our understanding of the Rub pathway in yeast and plants, work that is applicable to other organisms as well. There is a multi-subunit enzyme called SCF in all eukaryotes. The SCF consists of several subunits that serve as a scaffold (the cullin, SKP and RBX subunits) and one subunit that interacts with the substrate. This cullin protein (called Cdc53p in yeast and CULLIN 1 in plants and animals) was a known Rub target. In this work, we identified additional Rub targets in yeast as the other cullin-like proteins Cul3p and Rtt101p. Additionally we described the conservation of the Rub pathway because plant RUB1 can conjugated to yeast Cdc53p- in yeast. In the model plant Arabidopsis thaliana, we characterized the Rub activating enzymes and showed that they are not biochemically equivalent. We also showed that the Rub pathway is essential in plants and characterized plants with reduced levels of rub proteins. These plants are affected in multiple developmental processes. We discovered that they over-produce ethylene as dark-grown seedlings. We characterized a mutant allele of CULLIN1 in Arabidopsis with impaired interaction with RBX and showed that it is unstable in vivo. We used our knowledge of monitoring protein degradation to map the degradation determinants in a plant transcription factor. Finally, we took a mass spectrometric approach to identify novel Rub targets in plants and identified DDB1a, a subunit of an different ubiquitin ligase as a potential Rub-modified protein. Altogether, these studies have advanced our knowledge of the Rub pathway in all organisms
UA12/2/36 Scrapbook
No full textScrapbook chronicling Gamma Sigma Sigma activities and events of Fall 1973. Alpha Phi Omega Ball, Donna Bottoms, Glena Bryan, Sandy Busher, Dennis Callis, Susan Carr, Diane Carr, Elmer Crawford, Carroll Dant, Tina Davis, Amanda Davis, Rose Delafield Girls Club Durbin, Carla Galloway, Jeannie Gerard, Theresa Good, Francis Good, Warren Howels, Mike Hubbard, Paula Hutchins, Suzanne King, Mike Lightfoot, Barb Marsh, Charles Marsh, Valerie Marshall, Judy Morgan, Dianne Nugent, Kathy Patterson, Diane Patterson, James Reynolds, Nancy Rust, Judy Smith, Vickie Spencer, Dale Stersman, Joelynn Stinnett, Leigh Ware, Kathy Wilborn, Connie Williams, Allison Wuertz, Dav
Faculty Opinions recommendation of Identification of factors required for m6 A mRNA methylation in Arabidopsis reveals a role for the conserved E3 ubiquitin ligase HAKAI.
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Faculty Opinions recommendation of ATP sensing in living plant cells reveals tissue gradients and stress dynamics of energy physiology.
No full textFaculty Opinions recommendation of The F-box Protein KIB1 Mediates Brassinosteroid-Induced Inactivation and Degradation of GSK3-like Kinases in Arabidopsis.
No full textThe Ubiquitination Machinery of the Ubiquitin System
No full textThe protein ubiquitin is a covalent modifier of proteins, including itself. The ubiquitin system encompasses the enzymes required for catalysing attachment of ubiquitin to substrates as well as proteins that bind to ubiquitinated proteins leading them to their final fate. Also included are activities that remove ubiquitin independent of, or in concert with, proteolysis of the substrate, either by the proteasome or proteases in the vacuole. In addition to ubiquitin encoded by a family of fusion proteins, there are proteins with ubiquitin-like domains, likely forming ubiquitin's β-grasp fold, but incapable of covalent modification. However, they serve as protein-protein interaction platforms within the ubiquitin system. Multi-gene families encode all of these types of activities. Within the ubiquitination machinery "half" of the ubiquitin system are redundant, partially redundant, and unique components affecting diverse developmental and environmental responses in plants. Notably, multiple aspects of biotic and abiotic stress responses require, or are modulated by, ubiquitination. Finally, aspects of the ubiquitin system have broad utility: as components to enhance gene expression or to regulate protein abundance. This review focuses on the ubiquitination machinery: ubiquitin, unique aspects about the synthesis of ubiquitin and organization of its gene family, ubiquitin activating enzymes (E1), ubiquitin conjugating enzymes (E2) and ubiquitin ligases, or E3s. Given the large number of E3s in Arabidopsis this review covers the U box, HECT and RING type E3s, with the exception of the cullin-based E3s
Faculty Opinions recommendation of Reconstitution of the plant ubiquitination cascade in bacteria using a synthetic biology approach.
No full textRegulation of protein degradation
No full textThe intracellular level of a protein is dependent on both its rate of synthesis and its rate of degradation. Thus, differential regu-lation of protein stability represents a potential mechanism for modulating gene expression. lncreasing evidence suggest
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