Characterization of a novel RP2-OSTF1 interaction and its implication for actin remodelling

J Cell Sci. 2018 Feb 20;131(4):jcs211748. doi: 10.1242/jcs.211748.

Abstract

Retinitis pigmentosa 2 (RP2) is the causative gene for a form of X-linked retinal degeneration. RP2 was previously shown to have GTPase-activating protein (GAP) activity towards the small GTPase ARL3 via its N-terminus, but the function of the C-terminus remains elusive. Here, we report a novel interaction between RP2 and osteoclast-stimulating factor 1 (OSTF1), an intracellular protein that indirectly enhances osteoclast formation and activity and is a negative regulator of cell motility. Moreover, this interaction is abolished by a human pathogenic mutation in RP2. We utilized a structure-based approach to pinpoint the binding interface to a strictly conserved cluster of residues on the surface of RP2 that spans both the C- and N-terminal domains of the protein, and which is structurally distinct from the ARL3-binding site. In addition, we show that RP2 is a positive regulator of cell motility in vitro, recruiting OSTF1 to the cell membrane and preventing its interaction with the migration regulator Myo1E.

Keywords: Actin; OSTF1; RP2; Retinitis pigmentosa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factors / chemistry
  • ADP-Ribosylation Factors / genetics*
  • Actins / chemistry
  • Actins / genetics*
  • Binding Sites / genetics
  • Cell Line
  • Cell Membrane / genetics
  • Cell Membrane / metabolism
  • Cell Movement / genetics
  • Cilia / genetics
  • Cilia / metabolism
  • Eye Proteins / chemistry
  • Eye Proteins / genetics*
  • GTP-Binding Proteins
  • HEK293 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics*
  • Molecular Docking Simulation
  • Myosin Type I / chemistry
  • Myosin Type I / genetics
  • Protein Binding / genetics
  • Protein Conformation
  • Protein Domains / genetics
  • Protein Structure, Tertiary
  • Proteins / chemistry
  • Proteins / genetics*
  • Retina / metabolism
  • Retina / pathology
  • Retinal Degeneration / genetics
  • Retinal Degeneration / pathology
  • Retinitis Pigmentosa / genetics*
  • Retinitis Pigmentosa / metabolism
  • Retinitis Pigmentosa / pathology

Substances

  • Actins
  • Eye Proteins
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • OSTF1 protein, human
  • Proteins
  • RP2 protein, human
  • GTP-Binding Proteins
  • MYO1E protein, human
  • Myosin Type I
  • ADP-Ribosylation Factors
  • ARL3 protein, human

Supplementary concepts

  • Retinitis Pigmentosa 2