S. cerevisiae 26S protease mutants arrest cell division in G2/metaphase
Abstract
WE isolated two mutants from the yeast Saccharomyces cerevisiae,cim3-1 and cim5-1, that arrest cell division in G2/metaphase at 37 °C. CIM3 (identical to SUG1; ref. 1) and CIM5 are similar to each other and are members of a family of putative ATPases that have been proposed to be 26S protease subunits2. We show here that CIM5 is the functional yeast homologue of the human MSS1 protein3 and that homologues of CIM3 and CIM5 are present in a highly purified preparation of the Drosophila 26S protease4. The short-lived ubiquitin-proline-β-galactosidase fusion protein is stabilized in cim mutants, but Leu-β-galactosidase is not. The CLB2 and CLB3 cyclins also accumulate in the cim mutants. Thus the 26S protease is required in vivofor the degradation of ubiquitinated substrates and for anaphase chromosome separation.
- Publication:
-
Nature
- Pub Date:
- December 1993
- DOI:
- 10.1038/366358a0
- Bibcode:
- 1993Natur.366..358G