학술논문

Directed mutational scanning reveals a balance between acidic and hydrophobic residues in strong human activation domains
Document Type
article
Source
Cell Systems. 13(4)
Subject
Biochemistry and Cell Biology
Biological Sciences
Biotechnology
Amino Acid Sequence
DNA-Binding Proteins
Humans
Leucine
Transcription Factors
Transcriptional Activation
activation domain
all-atom simulations
deep mutational scanning
genomic method development
high-throughput mutagenesis
intrinsically disordered protein
intrinsically disordered region
transcription factor
Biochemistry and cell biology
Language
Abstract
Acidic activation domains are intrinsically disordered regions of the transcription factors that bind coactivators. The intrinsic disorder and low evolutionary conservation of activation domains have made it difficult to identify the sequence features that control activity. To address this problem, we designed thousands of variants in seven acidic activation domains and measured their activities with a high-throughput assay in human cell culture. We found that strong activation domain activity requires a balance between the number of acidic residues and aromatic and leucine residues. These findings motivated a predictor of acidic activation domains that scans the human proteome for clusters of aromatic and leucine residues embedded in regions of high acidity. This predictor identifies known activation domains and accurately predicts previously unidentified ones. Our results support a flexible acidic exposure model of activation domains in which the acidic residues solubilize hydrophobic motifs so that they can interact with coactivators. A record of this paper's transparent peer review process is included in the supplemental information.