Acetylation of intrinsically disordered regions regulates phase separation

• Published in: Nature chemical biology Vol. 15; no. 1; pp. 51 - 61
• Main Authors: Saito, Makoto, Hess, Daniel, Eglinger, Jan, Fritsch, Anatol W., Kreysing, Moritz, Weinert, Brian T., Choudhary, Chunaram, Matthias, Patrick
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.01.2019; Nature Publishing Group
• Subjects: 631/45; 631/80; 631/92/458; 631/92/475; Acetylation; Amyotrophic lateral sclerosis; Animals; Biochemical Engineering; Biochemistry; Biology; Bioorganic Chemistry; Catalytic Domain; Cell Biology; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Cytoplasmic Granules - metabolism; Deacetylation; DEAD-box RNA Helicases - metabolism; DNA helicase; Gene Knockout Techniques; Histone Deacetylase 6 - metabolism; Humans; Intrinsically Disordered Proteins - chemistry; Intrinsically Disordered Proteins - metabolism; Liquid phases; Lysine; Lysine - metabolism; Mice; Models, Theoretical; Mutation; Organelles; Osmotic Pressure; Phase separation; Proteins; Ribonucleic acid; RNA; RNA helicase; RNA Helicases - chemistry; RNA Helicases - genetics; RNA Helicases - metabolism; Substrates
• DOI: 10.1038/s41589-018-0180-7
• ISSN: 1552-4450; 1552-4469

Liquid–liquid phase separation (LLPS) of proteins containing intrinsically disordered regions (IDRs) has been proposed as a mechanism underlying the formation of membrane-less organelles. Tight regulation of IDR behavior is essential to ensure that LLPS only takes place when necessary. Here, we report that IDR acetylation/deacetylation regulates LLPS and assembly of stress granules (SGs), membrane-less organelles forming in response to stress. Acetylome analysis revealed that the RNA helicase DDX3X, an important component of SGs, is a novel substrate of the deacetylase HDAC6. The N-terminal IDR of DDX3X (IDR1) can undergo LLPS in vitro, and its acetylation at multiple lysine residues impairs the formation of liquid droplets. We also demonstrated that enhanced LLPS propensity through deacetylation of DDX3X-IDR1 by HDAC6 is necessary for SG maturation, but not initiation. Our analysis provides a mechanistic framework to understand how acetylation and deacetylation of IDRs regulate LLPS spatiotemporally, and impact membrane-less organelle formation in vivo. HDAC6 modulates acetylation at multiple lysine residues in the N-terminal intrinsically disordered region of RNA helicase DDX3X to regulate liquid–liquid phase separation and stress granule maturation.