Aberrant nuclear pore complex degradation contributes to neurodegeneration in VCP disease.

Abstract

Defective nucleocytoplasmic transport (NCT) has emerged as a contributing factor in the pathogenesis of neurodegenerative diseases and aging. Valosin-containing protein (VCP) is an AAA+ATPase required for disassembly of protein complexes, and mutations in VCP cause neurodegenerative and neuromuscular diseases. We find that VCP is required for quality control of nuclear pore complexes (NPCs) by extracting selected nucleoporins from NPCs for proteasome-mediated degradation. Pathogenic VCP variants cause a reduction in nucleoporins in Drosophila, induced pluripotent stem cell (iPSC)-derived motor neurons, and muscle biopsies from patients, indicating a dominant gain-of-function mechanism. Mechanistically, disease-associated mutations in VCP result in increased recruitment to NPCs through interactions with Ufd1-Npl4, leading to the removal of a subset of nucleoporins from NPCs and disrupting NCT. These findings show that the VCP-Ufd1-Npl4 pathway regulates NPC quality control and that disease-associated variants aberrantly activate the VCP-Ufd1-Npl4 complex to degrade NPCs and disrupt NCT.