A Proteasome Cap Subunit Required for Spindle Pole Body Duplication in Yeast
| Autor: | Breck Byers, Heather B. McDonald |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Proteasome Endopeptidase Complex
Saccharomyces cerevisiae Proteins Cell division Protein subunit Genes Fungal Molecular Sequence Data Saccharomyces cerevisiae Spindle Apparatus Protein degradation Protein Structure Secondary Article Spindle pole body Fungal Proteins 03 medical and health sciences 0302 clinical medicine Multienzyme Complexes Nuclear protein Ubiquitins Sequence Deletion 030304 developmental biology Adenosine Triphosphatases 0303 health sciences Base Sequence Sequence Homology Amino Acid biology Nuclear Proteins Cell Biology Cell cycle biology.organism_classification Cell Compartmentation Cell biology Spindle pole body duplication Cysteine Endopeptidases Biochemistry Sequence Alignment Cell Division 030217 neurology & neurosurgery |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.137.3.539 |
| Popis: | Proteasome-mediated protein degradation is a key regulatory mechanism in a diversity of complex processes, including the control of cell cycle progression. The selection of substrates for degradation clearly depends on the specificity of ubiquitination mechanisms, but further regulation may occur within the proteasomal 19S cap complexes, which attach to the ends of the 20S proteolytic core and are thought to control entry of substrates into the core. We have characterized a gene from Saccharomyces cerevisiae that displays extensive sequence similarity to members of a family of ATPases that are components of the 19S complex, including human subunit p42 and S. cerevisiae SUG1/ CIM3 and CIM5 products. This gene, termed PCS1 (for proteasomal cap subunit), is identical to the recently described SUG2 gene (Russell, S.J., U.G. Sathyanarayana, and S.A. Johnston. 1996. J. Biol. Chem. 271:32810– 32817). We have shown that PCS1 function is essential for viability. A temperature-sensitive pcs1 strain arrests principally in the second cycle after transfer to the restrictive temperature, blocking as large-budded cells with a G2 content of unsegregated DNA. EM reveals that each arrested pcs1 cell has failed to duplicate its spindle pole body (SPB), which becomes enlarged as in other monopolar mutants. Additionally, we have shown localization of a functional Pcs1–green fluorescent protein fusion to the nucleus throughout the cell cycle. We hypothesize that Pcs1p plays a role in the degradation of certain potentially nuclear component(s) in a manner that specifically is required for SPB duplication. |
| Databáze: | OpenAIRE |
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