Coordination of Grp1 recruitment mechanisms by its phosphorylation

Mol Biol Cell. 2020 Dec 1;31(25):2816-2825. doi: 10.1091/mbc.E20-03-0173. Epub 2020 Oct 7.


The action of guanine nucleotide exchange factors (GEFs) on the ADP-ribosylation factor (ARF) family of small GTPases initiates intracellular transport pathways. This role requires ARF GEFs to be recruited from the cytosol to intracellular membrane compartments. An ARF GEF known as General receptor for 3-phosphoinositides 1 (Grp1) is recruited to the plasma membrane through its pleckstrin homology (PH) domain that recognizes phosphatidylinositol 3,4,5-trisphosphate (PIP3). Here, we find that the phosphorylation of Grp1 induces its PH domain to recognize instead phosphatidylinositol 4-phosphate (PI4P). This phosphorylation also releases an autoinhibitory mechanism that results in the coil-coil (CC) domain of Grp1 engaging two peripheral membrane proteins of the recycling endosome. Because the combination of these actions results in Grp1 being recruited preferentially to the recycling endosome rather than to the plasma membrane, our findings reveal the complexity of recruitment mechanisms that need to be coordinated in localizing an ARF GEF to an intracellular compartment to initiate a transport pathway. Our elucidation is also remarkable for having revealed that phosphoinositide recognition by a PH domain can be switched through its phosphorylation.

Publication types

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

MeSH terms

  • 3T3-L1 Cells
  • ADP-Ribosylation Factors / metabolism
  • Amino Acid Sequence / genetics
  • Animals
  • Cell Membrane / metabolism
  • Guanine Nucleotide Exchange Factors / metabolism
  • Inositol Phosphates / metabolism
  • Intracellular Membranes / metabolism
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Intracellular Signaling Peptides and Proteins / physiology*
  • Membrane Proteins / metabolism*
  • Membrane Proteins / physiology*
  • Membrane Proteins / ultrastructure
  • Mice
  • Phosphatidylinositol Phosphates / metabolism*
  • Phosphatidylinositols / metabolism
  • Phosphorylation
  • Receptors, Cytoplasmic and Nuclear / metabolism


  • Guanine Nucleotide Exchange Factors
  • Inositol Phosphates
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Phosphatidylinositol Phosphates
  • Phosphatidylinositols
  • Receptors, Cytoplasmic and Nuclear
  • phosphatidylinositol 4-phosphate
  • phosphatidylinositol receptors
  • tamalin protein, mouse
  • ADP-Ribosylation Factors