title: Proteins with Intrinsically Disordered Domains Are Preferentially Recruited to Polyglutamine Aggregates.
abstract: Intracellular protein aggregation is the hallmark of several neurodegenerative diseases. Aggregates formed by polyglutamine (polyQ)-expanded proteins, such as Huntingtin, adopt amyloid-like structures that are resistant to denaturation. We used a novel purification strategy to isolate aggregates formed by human Huntingtin N-terminal fragments with expanded polyQ tracts from both yeast and mammalian (PC-12) cells. Using mass spectrometry we identified the protein species that are trapped within these polyQ aggregates. We found that proteins with very long intrinsically-disordered (ID) domains (≥ 100 amino acids) and RNA-binding proteins were disproportionately recruited into aggregates. The removal of the ID domains from selected proteins was sufficient to eliminate their recruitment into polyQ aggregates. We also observed that several neurodegenerative disease-linked proteins were reproducibly trapped within the polyQ aggregates purified from mammalian cells. Many of these proteins have large ID domains and are found in neuronal inclusions in their respective diseases. Our study indicates that neurodegenerative disease-associated proteins are particularly vulnerable to recruitment into polyQ aggregates via their ID domains. Also, the high frequency of ID domains in RNA-binding proteins may explain why RNA-binding proteins are frequently found in pathological inclusions in various neurodegenerative diseases.
authors: Department of Pharmacology, Uniformed Services University of the Heath Sciences, Bethesda, Maryland, 20814, United States of America.
authors: Maggie P
authors: MP
authors: Wear
authors: Department of Pharmacology, Uniformed Services University of the Heath Sciences, Bethesda, Maryland, 20814, United States of America.
authors: Dmitry
authors: D
authors: Kryndushkin
authors: Johns Hopkins Mass Spectrometry and Proteomic Facility, Johns Hopkins University, Baltimore, Maryland, 21218, United States of America.
authors: Robert
authors: R
authors: O'Meally
authors: Chemistry department, School of Sciences, Stevenson University, Stevenson, Maryland, 21153, United States of America.
authors: Jason L
authors: JL
authors: Sonnenberg
authors: Johns Hopkins Mass Spectrometry and Proteomic Facility, Johns Hopkins University, Baltimore, Maryland, 21218, United States of America.
authors: Robert N
authors: RN
authors: Cole
authors: Department of Pharmacology, Uniformed Services University of the Heath Sciences, Bethesda, Maryland, 20814, United States of America.
authors: Frank P
authors: FP
authors: Shewmaker
mesh_terms: D000818:Animals; D006801:Humans; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D066329:Protein Aggregates; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
chemical_list: C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D010455:Peptides; D066329:Protein Aggregates; D016601:RNA-Binding Proteins; C097188:polyglutamine