Unfolding of the C-terminal domain of the J-protein Zuo1 releases autoinhibition and activates Pdr1-dependent transcription. J Mol Biol 2013 Jan 09;425(1):19-31
Date
10/06/2012Pubmed ID
23036859Pubmed Central ID
PMC3534791DOI
10.1016/j.jmb.2012.09.020Scopus ID
2-s2.0-84871801279 (requires institutional sign-in at Scopus site) 31 CitationsAbstract
The C-terminal 69 residues of the J-protein Zuo1 are sufficient to activate Pdr1, a transcription factor involved in both pleiotropic drug resistance and growth control. Little is understood about the pathway of activation by this primarily ribosome associated Hsp40 co-chaperone. Here, we report that only the C-terminal 13 residues of Zuo1 are required for activation of Pdr1, with hydrophobic residues being critical for activity. Two-hybrid interaction experiments suggest that the interaction between this 13-residue Zuo1 peptide and Pdr1 is direct, analogous to the activation of Pdr1 by xenobiotics. However, simply dissociation of Zuo1 from the ribosome is not sufficient for induction of Pdr1 transcriptional activity, as the C-terminal 86 residues of Zuo1 fold into an autoinhibitory left-handed four-helix bundle. Hydrophobic residues critical for interaction with Pdr1 are sequestered within the structure of this C-terminal domain (CTD), necessitating unfolding for activation. Thus, although expression of the CTD does not result in activation, alterations that destabilize the structure cause induction of pleiotropic drug resistance. These destabilizing alterations also result in dissociation of the full-length protein from the ribosome. Thus, our results are consistent with an activation pathway in which unfolding of Zuo1's C-terminal helical bundle domain results in ribosome dissociation followed by activation of Pdr1 via a direct interaction.
Author List
Ducett JK, Peterson FC, Hoover LA, Prunuske AJ, Volkman BF, Craig EAAuthors
Francis C. Peterson PhD Professor in the Biochemistry department at Medical College of WisconsinAmy Jeanette Prunuske PhD Professor in the Medical School Regional Campuses department at Medical College of Wisconsin
Brian F. Volkman PhD Professor in the Biochemistry department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Amino Acid SequenceCycloheximide
DNA-Binding Proteins
Gene Expression Regulation, Fungal
Models, Molecular
Molecular Chaperones
Molecular Sequence Data
Point Mutation
Protein Interaction Mapping
Protein Structure, Secondary
Protein Structure, Tertiary
Protein Unfolding
Ribosomes
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins
Transcription Factors
Transcriptional Activation
Two-Hybrid System Techniques
