Protein interaction profiling of the p97 adaptor UBXD1 points to a role for the complex in modulating ERGIC-53 trafficking

Mol Cell Proteomics. 2012 Jun;11(6):M111.016444. doi: 10.1074/mcp.M111.016444. Epub 2012 Feb 14.

Abstract

UBXD1 is a member of the poorly understood subfamily of p97 adaptors that do not harbor a ubiquitin association domain or bind ubiquitin-modified proteins. Of clinical importance, p97 mutants found in familial neurodegenerative conditions Inclusion Body Myopathy Paget's disease of the bone and/or Frontotemporal Dementia and Amyotrophic Lateral Sclerosis are defective at interacting with UBXD1, indicating that functions regulated by a p97-UBXD1 complex are altered in these diseases. We have performed liquid chromatography-mass spectrometric analysis of UBXD1-interacting proteins to identify pathways in which UBXD1 functions. UBXD1 displays prominent association with ERGIC-53, a hexameric type I integral membrane protein that functions in protein trafficking. The UBXD1-ERGIC-53 interaction requires the N-terminal 10 residues of UBXD1 and the C-terminal cytoplasmic 12 amino acid tail of ERGIC-53. Use of p97 and E1 enzyme inhibitors indicate that complex formation between UBXD1 and ERGIC-53 requires the ATPase activity of p97, but not ubiquitin modification. We also performed SILAC-based quantitative proteomic profiling to identify ERGIC-53 interacting proteins. This analysis identified known (e.g. COPI subunits) and novel (Rab3GAP1/2 complex involved in the fusion of vesicles at the cell membrane) interactions that are also mediated through the C terminus of the protein. Immunoprecipitation and Western blotting analysis confirmed the proteomic interaction data and it also revealed that an UBXD1-Rab3GAP association requires the ERGIC-53 binding domain of UBXD1. Localization studies indicate that UBXD1 modules the sub-cellular trafficking of ERGIC-53, including promoting movement to the cell membrane. We propose that p97-UBXD1 modulates the trafficking of ERGIC-53-containing vesicles by controlling the interaction of transport factors with the cytoplasmic tail of ERGIC-53.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Adaptor Proteins, Vesicular Transport
  • Adenosine Triphosphatases / antagonists & inhibitors
  • Adenosine Triphosphatases / metabolism
  • Autophagy-Related Proteins
  • Benzoates / pharmacology
  • Carrier Proteins / chemistry
  • Carrier Proteins / metabolism*
  • Cell Line, Tumor
  • Furans / pharmacology
  • Humans
  • Mannose-Binding Lectins / chemistry
  • Mannose-Binding Lectins / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / metabolism
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Interaction Mapping
  • Protein Transport
  • Pyrazoles / pharmacology
  • Quinazolines / pharmacology
  • Secretory Vesicles / metabolism
  • Ubiquitin-Activating Enzymes / antagonists & inhibitors
  • Ubiquitin-Activating Enzymes / metabolism
  • rab3 GTP-Binding Proteins / metabolism

Substances

  • 4(4-(5-nitro-furan-2-ylmethylene)-3,5-dioxo-pyrazolidin-1-yl)-benzoic acid ethyl ester
  • Adaptor Proteins, Signal Transducing
  • Adaptor Proteins, Vesicular Transport
  • Autophagy-Related Proteins
  • Benzoates
  • Carrier Proteins
  • Furans
  • LMAN1 protein, human
  • Mannose-Binding Lectins
  • Membrane Proteins
  • N2,N4-dibenzylquinazoline-2,4-diamine
  • Nuclear Proteins
  • Pyrazoles
  • Quinazolines
  • UBXN6 protein, human
  • Adenosine Triphosphatases
  • p97 ATPase
  • rab3 GTP-Binding Proteins
  • Ubiquitin-Activating Enzymes