Delineation of functional subdomains of Huntingtin protein and their interaction with HAP40
Authors
- 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
Journal
- Structure
Citation
- Structure 31 (9): 1121-1131.e6
Abstract
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.