What question did this study set out to answer?

To identify and characterize the genetic and biochemical components of the ubiquitin fusion degradation (UFD) pathway in Saccharomyces cerevisiae.

July 1, 1995Journal of Biological ChemistryOpen Access

A Proteolytic Pathway That Recognizes Ubiquitin as a Degradation Signal

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Authors

EJErica S. JohnsonThomas Jefferson University PCPhilip C.M.California Institute of Technology IOIrene M. OtaCalifornia Institute of Technology

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Implication

Genetic analysis uncovers the ubiquitin fusion degradation pathway in yeast, indicating distinct functions for Lys29 and Lys48 linkages in targeted proteolysis.

Key Points

To identify and characterize the genetic and biochemical components of the ubiquitin fusion degradation (UFD) pathway in Saccharomyces cerevisiae.
Screened and analyzed yeast mutants (ufd1 through ufd5) deficient in degrading fusion proteins containing nonremovable N-terminal ubiquitin moieties.
Cloned and sequenced the identified UFD genes and evaluated sequence homology to known mammalian proteins.
Tested the impact of specific ubiquitin mutations (Lys to Arg conversions at positions 29 and 48) on multi-ubiquitin chain formation and substrate degradation using beta-galactosidase and dihydrofolate reductase fusions.
Identified five pathway components: Ufd1p and Ufd5p act at post-ubiquitination steps; Ufd3p regulates free ubiquitin pools; and Ufd2p and Ufd4p determine multi-ubiquitin chain assembly.
Demonstrated that Ufd4p shares sequence homology with human E6AP, and Ufd5p is identical to the nuclear transport suppressor Son1p and is required for both the UFD and N-end rule pathways.
Showed that multi-ubiquitin chain formation relies on Lys29 linkages mediated by Ufd4p and Lys48 linkages mediated by Ufd2p, with substrate-specific degradation requirements.

Cite This Study

Johnson et al. (1995) studied this question.

synapsesocial.com/papers/6a12efd406ed52b5c2c0cd16 https://doi.org/10.1074/jbc.270.29.17442

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Implication

Genetic analysis uncovers the ubiquitin fusion degradation pathway in yeast, indicating distinct functions for Lys29 and Lys48 linkages in targeted proteolysis.

A Proteolytic Pathway That Recognizes Ubiquitin as a Degradation Signal

Discussion

Member takes

Implication

Key Points

Cite This Study

A Proteolytic Pathway That Recognizes Ubiquitin as a Degradation Signal

Discussion

Member takes

Implication

Key Points

Cite This Study

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