Arrestin-1 engineering facilitates complex stabilization with native rhodopsin

Sci Rep. 2019 Jan 24;9(1):439. doi: 10.1038/s41598-018-36881-4.

Abstract

Arrestin-1 desensitizes the activated and phosphorylated photoreceptor rhodopsin by forming transient rhodopsin-arrestin-1 complexes that eventually decay to opsin, retinal and arrestin-1. Via a multi-dimensional screening setup, we identified and combined arrestin-1 mutants that form lasting complexes with light-activated and phosphorylated rhodopsin in harsh conditions, such as high ionic salt concentration. Two quadruple mutants, D303A + T304A + E341A + F375A and R171A + T304A + E341A + F375A share similar heterologous expression and thermo-stability levels with wild type (WT) arrestin-1, but are able to stabilize complexes with rhodopsin with more than seven times higher half-maximal inhibitory concentration (IC50) values for NaCl compared to the WT arrestin-1 protein. These quadruple mutants are also characterized by higher binding affinities to phosphorylated rhodopsin, light-activated rhodopsin and phosphorylated opsin, as compared with WT arrestin-1. Furthermore, the assessed arrestin-1 mutants are still specifically associating with phosphorylated or light-activated receptor states only, while binding to the inactive ground state of the receptor is not significantly altered. Additionally, we propose a novel functionality for R171 in stabilizing the inactive arrestin-1 conformation as well as the rhodopsin-arrestin-1 complex. The achieved stabilization of the active rhodopsin-arrestin-1 complex might be of great interest for future structure determination, antibody development studies as well as drug-screening efforts targeting G protein-coupled receptors (GPCRs).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arrestins / chemistry
  • Arrestins / genetics
  • Arrestins / metabolism*
  • Cattle
  • HEK293 Cells
  • Humans
  • Models, Molecular
  • Multiprotein Complexes / chemistry
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / metabolism*
  • Mutation
  • Opsins / chemistry
  • Opsins / metabolism*
  • Phosphorylation
  • Protein Binding
  • Protein Conformation
  • Protein Engineering / methods*
  • Protein Stability
  • Rhodopsin / chemistry
  • Rhodopsin / metabolism*

Substances

  • Arrestins
  • Multiprotein Complexes
  • Opsins
  • Rhodopsin