The Gal4 activation domain binds Sug2 protein, a proteasome component, in vivo and in vitro.
An in vivo protein interaction assay was used to search a yeast cDNA library for proteins that bind to the acidic activation domain (AD) of the yeast Gal4 protein. Sug2 protein, a component of the 19 S regulatory particle of the 26 S proteasome, was one of seven proteins identified in this screen. In vitro binding assays confirm a direct interaction between these proteins. SUG2 and SUG1, another 19 S component, were originally discovered as a mutation able to suppress the phenotype of a Gal4 truncation mutant (Gal4(D)p) lacking much of its AD. Sug1p has previously been shown to bind the Gal4 AD in vitro. Taken together, these genetic and biochemical data suggest a biologically significant interaction between the Gal4 protein and the 19 S regulatory particle of the proteasome. Indeed, it is demonstrated here that the Gal4 AD interacts specifically with immunopurified 19 S complex. The proteasome regulatory particle has been shown recently to play a direct role in RNA polymerase II transcription and the activator-19 S interaction could be important in recruiting this large complex to transcriptionally active GAL genes.
Chang
C
C
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8573, USA.
Gonzalez
F
F
Rothermel
B
B
Sun
L
L
Johnston
S A
SA
Kodadek
T
T
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001549:Benzamides; D001665:Binding Sites; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004268:DNA-Binding Proteins; D019281:Dimerization; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D011401:Promoter Regions, Genetic; D046988:Proteasome Endopeptidase Complex; D011817:Rabbits; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000235:genetics
D001549:Benzamides; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014443:Tyrosine; C012614:1-nitrohydroxyphenyl-N-benzoylalanine; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; C103015:RPT4 protein, S cerevisiae