Arabidopsis MBP1 gene encodes a conserved ubiquitin recognition component of the 26S proteasome
- Univ. of Wisconsin, Madison, WI (United States)
- Univ. of Utah School of Medicine, Salt Lake City, UT (United States); and others
Multiubiquitin chain attachment is a key step leading to the selective degradation of abnormal polypeptides and many important regulatory proteins by the eukaryotic 26S proteasome. However, the mechanism by which the 26S complex recognizes this posttranslational modification is unknown. Using synthetic multiubiquitin chains to probe an expression library for interacting proteins, we have isolated an Arabidopsis cDNA, designated MBP1, that encodes a 41-kDa acidic protein exhibiting high affinity for chains, especially those containing four or more ubiquitins. Based on similar physical and immunological properties, multiubiquitin binding affinities, and peptide sequence, MBP1 is homologous to subunit 5a of the human 26S proteasome. Structurally related proteins also exist in yeast, Caenorhabditis, and other plant species. Given their binding properties, association with the 26S proteasome, and widespread distribution, MBP1, S5a, and related proteins likely function as essential ubiquitin recognition components of the 26S proteasome. 35 refs., 3 figs.
- OSTI ID:
- 258619
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 93, Issue 2; Other Information: PBD: 23 Jan 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Molecular Dissection of the Arabidopsis 26S Proteasome
The ubiquitin-interacting motifs of S5a as a unique upstream inhibitor of the 26S proteasome