The Na,K-ATPase acts upstream of phosphoinositide PI(4,5)P2 facilitating unconventional secretion of Fibroblast Growth Factor 2

Commun Biol. 2020 Mar 25;3(1):141. doi: 10.1038/s42003-020-0871-y.

Abstract

FGF2 is a tumor cell survival factor that is exported from cells by an ER/Golgi-independent secretory pathway. This unconventional mechanism of protein secretion is based on direct translocation of FGF2 across the plasma membrane. The Na,K-ATPase has previously been shown to play a role in this process, however, the underlying mechanism has remained elusive. Here, we define structural elements that are critical for a direct physical interaction between FGF2 and the α1 subunit of the Na,K-ATPase. In intact cells, corresponding FGF2 mutant forms were impaired regarding both recruitment at the inner plasma membrane leaflet and secretion. Ouabain, a drug that inhibits both the Na,K-ATPase and FGF2 secretion, was found to impair the interaction of FGF2 with the Na,K-ATPase in cells. Our findings reveal the Na,K-ATPase as the initial recruitment factor for FGF2 at the inner plasma membrane leaflet being required for efficient membrane translocation of FGF2 to cell surfaces.

Publication types

  • Research Support, Non-U.S. Gov't
  • Video-Audio Media

MeSH terms

  • Animals
  • CHO Cells
  • Cell Membrane / enzymology*
  • Cricetulus
  • Fibroblast Growth Factor 2 / chemistry
  • Fibroblast Growth Factor 2 / genetics
  • Fibroblast Growth Factor 2 / metabolism*
  • Molecular Docking Simulation
  • Molecular Dynamics Simulation
  • Phosphatidylinositol 4,5-Diphosphate / metabolism*
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Transport
  • Second Messenger Systems
  • Secretory Pathway
  • Sodium-Potassium-Exchanging ATPase / chemistry
  • Sodium-Potassium-Exchanging ATPase / genetics
  • Sodium-Potassium-Exchanging ATPase / metabolism*

Substances

  • Phosphatidylinositol 4,5-Diphosphate
  • Fibroblast Growth Factor 2
  • ATP1A1 protein, human
  • Sodium-Potassium-Exchanging ATPase