Huntingtin-associated protein 1 (HAP1) interacts with the p150Glued subunit of dynactin

Hum Mol Genet. 1997 Dec;6(13):2205-12. doi: 10.1093/hmg/6.13.2205.

Abstract

Huntington's disease (HD) is an inherited neurodegenerative disease caused by expansion of a polyglutamine repeat in the HD protein huntingtin. Huntingtin's localization within the cell includes an association with cytoskeletal elements and vesicles. We previously identified a protein (HAP1) which binds to huntingtin in a glutamine repeat length-dependent manner. We now report that HAP1 interacts with cytoskeletal proteins, namely the p150 Glued subunit of dynactin and the pericentriolar protein PCM-1. Structural predictions indicate that both HAP1 and the interacting proteins have a high probability of forming coiled coils. We examined the interaction of HAP1 with p150 Glued . Binding of HAP1 to p150 Glued (amino acids 879-1150) was confirmed in vitro by binding of p150 Glued to a HAP1-GST fusion protein immobilized on glutathione-Sepharose beads. Also, HAP1 co-immunoprecipitated with p150 Glued from brain extracts, indicating that the interaction occurs in vivo . Like HAP1, p150 Glued is highly expressed in neurons in brain and both proteins are enriched in a nerve terminal vesicle-rich fraction. Double label immunofluorescence experiments in NGF-treated PC12 cells using confocal microscopy revealed that HAP1 and p150 Glued partially co-localize. These results suggest that HAP1 might function as an adaptor protein using coiled coils to mediate interactions among cytoskeletal, vesicular and motor proteins. Thus, HAP1 and huntingtin may play a role in vesicle trafficking within the cell and disruption of this function could contribute to the neuronal dysfunction and death seen in HD.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Autoantigens / metabolism
  • Base Sequence
  • Brain Chemistry
  • Carbon-Oxygen Lyases*
  • Cell Cycle Proteins*
  • Cell Line
  • Chromatography, Affinity
  • Cytoskeleton / metabolism
  • Cytoskeleton / ultrastructure
  • DNA, Complementary / genetics
  • DNA-(Apurinic or Apyrimidinic Site) Lyase*
  • Dynactin Complex
  • Humans
  • Kinesin / genetics
  • Macromolecular Substances
  • Microscopy, Confocal
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / metabolism*
  • Molecular Sequence Data
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / metabolism*
  • PC12 Cells
  • Protein Binding
  • Protein Conformation
  • Rats
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins

Substances

  • Autoantigens
  • Cell Cycle Proteins
  • DCTN1 protein, human
  • DNA, Complementary
  • Dynactin Complex
  • Macromolecular Substances
  • Microtubule-Associated Proteins
  • NIP100 protein, S cerevisiae
  • Nuclear Proteins
  • PCM1 protein, human
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Kinesin
  • Carbon-Oxygen Lyases
  • APEX1 protein, human
  • Apex1 protein, rat
  • DNA-(Apurinic or Apyrimidinic Site) Lyase

Associated data

  • GENBANK/AF010146