The slow Wallerian degeneration protein, WldS, binds directly to VCP/p97 and partially redistributes it within the nucleus

Mol Biol Cell. 2006 Mar;17(3):1075-84. doi: 10.1091/mbc.e05-04-0375. Epub 2005 Dec 21.

Abstract

Slow Wallerian degeneration (Wld(S)) mutant mice express a chimeric nuclear protein that protects sick or injured axons from degeneration. The C-terminal region, derived from NAD(+) synthesizing enzyme Nmnat1, is reported to confer neuroprotection in vitro. However, an additional role for the N-terminal 70 amino acids (N70), derived from multiubiquitination factor Ube4b, has not been excluded. In wild-type Ube4b, N70 is part of a sequence essential for ubiquitination activity but its role is not understood. We report direct binding of N70 to valosin-containing protein (VCP; p97/Cdc48), a protein with diverse cellular roles including a pivotal role in the ubiquitin proteasome system. Interaction with Wld(S) targets VCP to discrete intranuclear foci where ubiquitin epitopes can also accumulate. Wld(S) lacking its N-terminal 16 amino acids (N16) neither binds nor redistributes VCP, but continues to accumulate in intranuclear foci, targeting its intrinsic NAD(+) synthesis activity to these same foci. Wild-type Ube4b also requires N16 to bind VCP, despite a more C-terminal binding site in invertebrate orthologues. We conclude that N-terminal sequences of Wld(S) protein influence the intranuclear location of both ubiquitin proteasome and NAD(+) synthesis machinery and that an evolutionary recent sequence mediates binding of mammalian Ube4b to VCP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases
  • Amino Acid Sequence
  • Animals
  • COS Cells
  • Cell Cycle Proteins / chemistry
  • Cell Cycle Proteins / metabolism*
  • Cell Nucleus / metabolism*
  • Cells, Cultured
  • Chlorocebus aethiops
  • Evolution, Molecular
  • HeLa Cells
  • Humans
  • Intranuclear Space / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Molecular Sequence Data
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / metabolism*
  • Nicotinamide-Nucleotide Adenylyltransferase / metabolism
  • Protein Binding
  • Protein Transport
  • Rats
  • Recombinant Fusion Proteins / metabolism
  • Ubiquitin / metabolism
  • Valosin Containing Protein

Substances

  • Cell Cycle Proteins
  • Nerve Tissue Proteins
  • Recombinant Fusion Proteins
  • Ubiquitin
  • Wld protein, mouse
  • Nicotinamide-Nucleotide Adenylyltransferase
  • Nmnat1 protein, mouse
  • Adenosine Triphosphatases
  • VCP protein, human
  • Valosin Containing Protein
  • Vcp protein, mouse
  • Vcp protein, rat