The cytohesin coiled-coil domain interacts with threonine 276 to control membrane association

PLoS One. 2013 Nov 26;8(11):e82084. doi: 10.1371/journal.pone.0082084. eCollection 2013.

Abstract

Cell migration is regulated by a number of small GTPases, including members of the Arf family. Cytohesins, a family of Arf-activating proteins, have been extensively implicated in the regulation of Arfs during migration and cell shape change. Membrane association of both the Arf and its activating protein is a prerequisite for Arf activation. Therefore regulating the extent of cytohesin membrane association is a mechanism for controlling the initiation of cell movement. We have discovered a novel intramolecular interaction that controls the association of cytohesins with membranes. The presence of the coiled-coil domain reduces the association of cytohesin 2 with membranes. We demonstrate that this domain interacts with more C-terminal regions of the protein. This interaction is independent of another previously identified autoinhibitory conformation. A threonine residue (T276) in the cytohesin 2 PH domain is a target for phosphorylation by Akt. Mutation of this threonine to aspartic acid, to mimic phosphorylation, disrupts the binding of the coiled-coil domain to c-terminal regions and promotes membrane association of cytohesin 2. The presence of a second autoinhibitory interaction in the cytohesins suggests that these proteins can act a signal integrators that stimulate migration only after receive multiple pro-migratory signals.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Line
  • Cell Membrane / metabolism*
  • GTPase-Activating Proteins / chemistry
  • GTPase-Activating Proteins / metabolism*
  • Models, Biological
  • Phosphorylation
  • Protein Binding
  • Protein Interaction Domains and Motifs*
  • Protein Transport
  • Proto-Oncogene Proteins c-akt / metabolism
  • Threonine / metabolism*

Substances

  • GTPase-Activating Proteins
  • cytohesin-2
  • Threonine
  • Proto-Oncogene Proteins c-akt