A mutation in VAPB that causes amyotrophic lateral sclerosis also causes a nuclear envelope defect

J Cell Sci. 2012 Jun 15;125(Pt 12):2831-6. doi: 10.1242/jcs.102111. Epub 2012 Mar 27.

Abstract

A proline to serine mutation (P56S) in vesicle-associated membrane protein-associated protein B and C (VAPB) causes an autosomal dominant form of amyotrophic lateral sclerosis (ALS). We show that the mutation also causes a nuclear envelope defect. Transport of nucleoporins (Nups) and emerin (EMD) to the nuclear envelope is blocked, resulting in their sequestration in dilated cytoplasmic membranes. Simultaneous overexpression of the FFAT motif (two phenylalanine residues in an acidic track) antagonizes the effect of mutant VAPB and restores transport to the nuclear envelope. VAPB function is required for transport to the nuclear envelope, with knockdown of endogenous VAPB recapitulating this phenotype. Moreover, we identified the compartment into which the Nups and EMD were sequestered as the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC), with nuclear envelope membrane proteins transiting to the ERGIC before VAPB-dependent retrograde transport to the nuclear envelope.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyotrophic Lateral Sclerosis / genetics*
  • Amyotrophic Lateral Sclerosis / metabolism*
  • HeLa Cells
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mutation*
  • Nuclear Envelope / genetics
  • Nuclear Envelope / metabolism*
  • Nuclear Pore Complex Proteins / genetics
  • Nuclear Pore Complex Proteins / metabolism
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Protein Transport
  • Vesicular Transport Proteins / genetics*
  • Vesicular Transport Proteins / metabolism

Substances

  • Membrane Proteins
  • Nuclear Pore Complex Proteins
  • Nuclear Proteins
  • VAPB protein, human
  • Vesicular Transport Proteins
  • emerin