Delineation of functional subdomains of Huntingtin protein and their interaction with HAP40


  • M.G. Alteen
  • J.C. Deme
  • C.P. Alvarez
  • P. Loppnau
  • A. Hutchinson
  • A. Seitova
  • R. Chandrasekaran
  • E. Silva Ramos
  • C. Secker
  • M. Alqazzaz
  • E.E. Wanker
  • S.M. Lea
  • C.H. Arrowsmith
  • R.J. Harding


  • Structure


  • Structure 31 (9): 1121-1131.e6


  • The huntingtin (HTT) protein plays critical roles in numerous cellular pathways by functioning as a scaffold for its many interaction partners and HTT knock out is embryonic lethal. Interrogation of HTT function is complicated by the large size of this protein so we studied a suite of structure-rationalized subdomains to investigate the structure-function relationships within the HTT-HAP40 complex. Protein samples derived from the subdomain constructs were validated using biophysical methods and cryo-electron microscopy, revealing they are natively folded and can complex with validated binding partner, HAP40. Derivatized versions of these constructs enable protein-protein interaction assays in vitro, with biotin tags, and in cells, with luciferase two-hybrid assay-based tags, which we use in proof-of-principle analyses to further interrogate the HTT-HAP40 interaction. These open-source biochemical tools enable studies of fundamental HTT biochemistry and biology, will aid the discovery of macromolecular or small-molecule binding partners and help map interaction sites across this large protein.