RT Journal Article
SR Electronic
T1 A deep mutational scan of an acidic activation domain
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 230987
DO 10.1101/230987
A1 Max V. Staller
A1 Alex S. Holehouse
A1 Devjanee Swain-Lenz
A1 Rahul K. Das
A1 Rohit V. Pappu
A1 Barak A. Cohen
YR 2017
UL http://biorxiv.org/content/early/2017/12/08/230987.abstract
AB Transcriptional activation domains are intrinsically disordered peptides with little primary sequence conservation. These properties have made it difficult to identify the sequence features that define activation domains. For example, although acidic activation domains were discovered 30 years ago, we still do not know what role, if any, acidic residues play in these peptides. To address this question we designed a rational mutagenesis scheme to independently test four sequence features theorized to control the strength of activation domains: acidity (negative charge), hydrophobicity, intrinsic disorder, and short linear motifs. To test enough mutants to deconvolve these four features we developed a method to quantify the activities of thousands of activation domain variants in parallel. Our results with Gcn4, a classic acidic activation domain, suggest that acidic residues in particular regions keep two hydrophobic motifs exposed to solvent. We also found that the specific activity of the Gcn4 activation domain increases during amino acid starvation. Our results suggest that Gcn4 may have evolved to have low activity but high inducibility. Our results also demonstrate that high-throughput rational mutation scans will be powerful tools for unraveling the properties that control how intrinsically disordered proteins function.