ausblenden:
Schlagwörter:
Alanine
Base Sequence
Blotting, Western
*Carrier Proteins
Codon
Cysteine Endopeptidases/*metabolism
Electrophoresis, Polyacrylamide Gel
Fluorescence
Glycine
Green Fluorescent Proteins
HeLa Cells
Herpesvirus 4, Human/genetics
Humans
Luminescent Proteins/genetics/metabolism
Membrane Proteins/metabolism
Methionine/metabolism
Molecular Sequence Data
Multienzyme Complexes/*antagonists & inhibitors/metabolism
Proteasome Endopeptidase Complex
Recombinant Fusion Proteins/genetics/metabolism
*Repetitive Sequences, Nucleic Acid
Repressor Proteins/metabolism
Saccharomyces cerevisiae/genetics/*metabolism
Saccharomyces cerevisiae Proteins/metabolism
Ubiquitin/antagonists & inhibitors/genetics/*metabolism
Zusammenfassung:
The glycine-alanine (GA) repeat of the Epstein-Barr virus nuclear antigen-1 inhibits in cis ubiquitin-dependent proteolysis in mammalian cells through a yet unknown mechanism. In the present study we demonstrate that the GA repeat targets an evolutionarily conserved step in proteolysis since it can prevent the degradation of proteasomal substrates in the yeast Saccharomyces cerevisiae. Insertion of yeast codon-optimised recombinant GA (rGA) repeats of different length in green fluorescent protein reporters harbouring N-end rule or ubiquitin fusion degradation signals resulted in efficient stabilisation of these substrates. Protection was also achieved in rpn10delta yeast suggesting that this polyubiquitin binding protein is not required for the rGA effect. The conserved effect of the GA repeat in yeast opens the possibility for the use of genetic screens to unravel its mode of action.
