Specific and direct modulation of the interaction between adhesion GPCR GPR56/ADGRG1 and tissue transglutaminase 2 using synthetic ligands

Sci Rep. 2020 Oct 9;10(1):16912. doi: 10.1038/s41598-020-74044-6.

Abstract

Blocking the interaction between cell-surface receptors and their ligands is a proven therapeutic strategy. Adhesion G protein-coupled receptors (aGPCRs) are key cell-surface receptors that regulate numerous pathophysiological processes, and their large extracellular regions (ECRs) mediate ligand binding and function. The aGPCR GPR56/ADGRG1 regulates central nervous system myelination and melanoma progression by interacting with its ligand, tissue transglutaminase 2 (TG2), but the molecular basis for this interaction is largely undefined. Here, we show that the C-terminal portion of TG2 directly interacted with the GPR56 ECR with high-nanomolar affinity, and used site-directed mutagenesis to identify a patch of conserved residues on the pentraxin/laminin-neurexin-sex-hormone-binding-globulin-like (PLL) domain of GPR56 as the TG2 binding site. Importantly, we also show that the GPR56-TG2 interaction was blocked by previously-reported synthetic proteins, termed monobodies, that bind the GPR56 ECR in a domain- and species-specific manner. This work provides unique tools to modulate aGPCR-ligand binding and establishes a foundation for the development of aGPCR-targeted therapeutics.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites / physiology
  • Cell Adhesion / physiology*
  • Cells, Cultured
  • GTP-Binding Proteins / metabolism*
  • HEK293 Cells
  • Humans
  • Insecta
  • Ligands
  • Mammals / metabolism
  • Protein Binding / physiology
  • Protein Domains / physiology
  • Receptors, G-Protein-Coupled / metabolism*
  • Signal Transduction / physiology
  • Transglutaminases / metabolism*

Substances

  • ADGRG1 protein, human
  • Ligands
  • Receptors, G-Protein-Coupled
  • transglutaminase 2
  • Transglutaminases
  • GTP-Binding Proteins