VPS26 Moonlights as a β-Arrestin-like Adapter for a 7-Transmembrane RGS Protein in Arabidopsis thaliana

Biochemistry. 2024 Nov 19;63(22):2990-2999. doi: 10.1021/acs.biochem.4c00361. Epub 2024 Oct 28.

Abstract

Extracellular signals perceived by 7-transmembrane (7TM)-spanning receptors initiate desensitization that involves the removal of these receptors from the plasma membrane. Agonist binding often evokes phosphorylation in the flexible C-terminal region and/or intracellular loop 3 of many 7TM G-protein-coupled receptors in animal cells, which consequently recruits a cytoplasmic intermediate adaptor, β-arrestin, resulting in clathrin-mediated endocytosis (CME) and downstream signaling such as transcriptional changes. Some 7TM receptors undergo CME without recruiting β-arrestin, but it is not clear how. Arrestins are not encoded in the Arabidopsis thaliana genome, yet Arabidopsis cells have a well-characterized signal-induced CME of a 7TM protein, designated Regulator of G Signaling 1 (AtRGS1). Here we show that a component of the retromer complex, Vacuolar Protein Sorting-Associated 26 (VPS26), binds the phosphorylated C-terminal region of AtRGS1 as a VPS26A/B heterodimer to form a complex that is required for downstream signaling. We propose that VPS26 moonlights as an arrestin-like adaptor in the CME of AtRGS1.

MeSH terms

  • Arabidopsis Proteins* / chemistry
  • Arabidopsis Proteins* / genetics
  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / genetics
  • Arabidopsis* / metabolism
  • Endocytosis* / physiology
  • Phosphorylation
  • Protein Binding
  • RGS Proteins / chemistry
  • RGS Proteins / genetics
  • RGS Proteins / metabolism
  • Signal Transduction
  • Vesicular Transport Proteins / chemistry
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism
  • beta-Arrestins / metabolism

Substances

  • Arabidopsis Proteins
  • RGS Proteins
  • beta-Arrestins
  • Vesicular Transport Proteins