title: AAA ATPase p97/VCP is essential for TRIM21-mediated virus neutralization.
abstract: Tripartite motif-containing 21 (TRIM21) is a cytosolic IgG receptor that mediates intracellular virus neutralization by antibody. TRIM21 targets virions for destruction in the proteasome, but it is unclear how a substrate as large as a viral capsid is degraded. Here, we identify the ATPase p97/valosin-containing protein (VCP), an enzyme with segregase and unfoldase activity, as a key player in this process. Depletion or catalytic inhibition of VCP prevents capsid degradation and reduces neutralization. VCP is required concurrently with the proteasome, as addition of inhibitor after proteasomal degradation has no effect. Moreover, our results suggest that it is the challenging nature of virus as a substrate that necessitates involvement of VCP, since intracellularly expressed IgG Fc is degraded in a VCP-independent manner. These results implicate VCP as an important host factor in antiviral immunity.
authors.affiliation: Protein and Nucleic Acid Chemistry Division,  Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH,  United Kingdom.
authors.forename: Felix
authors.initials: F
authors.lastname: Hauler
authors.forename: Donna L
authors.initials: DL
authors.lastname: Mallery
authors.forename: William A
authors.initials: WA
authors.lastname: McEwan
authors.forename: Susanna R
authors.initials: SR
authors.lastname: Bidgood
authors.forename: Leo C
authors.initials: LC
authors.lastname: James
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D002384:Catalysis; D018797:Cell Cycle Proteins / Q000378:metabolism*; D006801:Humans; D009500:Neutralization Tests; D012261:Ribonucleoproteins / Q000502:physiology*; D000074405:Valosin Containing Protein; D000099207:SS-A Antigen
chemical_list: D000251:Adenosine Triphosphatases; D018797:Cell Cycle Proteins; D012261:Ribonucleoproteins; D000074405:Valosin Containing Protein; D000099207:SS-A Antigen; C000614178:VCP protein, human