title: An ALS disease mutation in Cdc48/p97 impairs 20S proteasome binding and proteolytic communication.
abstract: Cdc48 (also known as p97 or VCP) is an essential and highly abundant, double-ring AAA+ ATPase, which is ubiquitous in archaea and eukaryotes. In archaea, Cdc48 ring hexamers play a direct role in quality control by unfolding and translocating protein substrates into the degradation chamber of the 20S proteasome. Whether Cdc48 and 20S cooperate directly in protein degradation in eukaryotic cells is unclear. Two regions of Cdc48 are important for 20S binding, the pore-2 loop at the bottom of the D2 AAA+ ring and a C-terminal tripeptide. Here, we identify an aspartic acid in the pore-2 loop as an important element in 20S recognition. Importantly, mutation of this aspartate in human Cdc48 has been linked to familial amyotrophic lateral sclerosis (ALS). In archaeal or human Cdc48 variants, we find that mutation of this pore-2 residue impairs 20S binding and proteolytic communication but does not affect the stability of the hexamer or rates of ATP hydrolysis and protein unfolding. These results suggest that human Cdc48 interacts functionally with the 20S proteasome.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139.
authors.forename: Dominik
authors.initials: D
authors.lastname: Barthelme
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139.
authors.forename: Ruben
authors.initials: R
authors.lastname: Jauregui
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Sauer
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000690:Amyotrophic Lateral Sclerosis / Q000201:enzymology* / Q000235:genetics*; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D008958:Models, Molecular; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D058767:Protein Unfolding; D059748:Proteolysis; D000074405:Valosin Containing Protein
chemical_list: D018797:Cell Cycle Proteins; D001224:Aspartic Acid; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; C000614178:VCP protein, human; D000074405:Valosin Containing Protein
keywords: AAA+ machine; ATP-dependent degradation; proteasome; protein unfolding