Ubiquitin as a degradation signal.
EMBO J
; 11(2): 497-505, 1992 Feb.
Article
en En
| MEDLINE
| ID: mdl-1311250
ABSTRACT
For many short-lived eukaryotic proteins, conjugation to ubiquitin, yielding a multiubiquitin chain, is an obligatory pre-degradation step. The conjugated ubiquitin moieties function as a 'secondary' signal for degradation, in that their posttranslational coupling to a substrate protein is mediated by amino acid sequences of the substrate that act as a primary degradation signal. We report that the fusion protein ubiquitin--proline--beta-galactosidase (Ub-P-beta gal) is short-lived in the yeast Saccharomyces cerevisiae because its N-terminal ubiquitin moiety functions as an autonomous, primary degradation signal. This signal mediates the formation of a multiubiquitin chain linked to Lys48 of the N-terminal ubiquitin in Ub-P-beta gal. The degradation of Ub-P-beta gal is shown to require Ubc4, one of at least seven ubiquitin-conjugating enzymes in S.cerevisiae. Our findings provide the first direct evidence that a monoubiquitin moiety can function as an autonomous degradation signal. This generally applicable, cis-acting signal can be used to manipulate the in vivo half-lives of specific intracellular proteins.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
/
Ubiquitinas
/
Transducción de Señal
Idioma:
En
Revista:
EMBO J
Año:
1992
Tipo del documento:
Article