Role of phosphatidylinositol 4,5-bisphosphate in regulating EHD2 plasma membrane localization

PLoS One. 2013 Sep 10;8(9):e74519. doi: 10.1371/journal.pone.0074519. eCollection 2013.

Abstract

The four mammalian C-terminal Eps15 homology domain-containing proteins (EHD1-EHD4) play pivotal roles in endocytic membrane trafficking. While EHD1, EHD3 and EHD4 associate with intracellular tubular/vesicular membranes, EHD2 localizes to the inner leaflet of the plasma membrane. Currently, little is known about the regulation of EHD2. Thus, we sought to define the factors responsible for EHD2's association with the plasma membrane. The subcellular localization of endogenous EHD2 was examined in HeLa cells using confocal microscopy. Although EHD partner proteins typically mediate EHD membrane recruitment, EHD2 was targeted to the plasma membrane independent of two well-characterized binding proteins, syndapin2 and EHBP1. Additionally, the EH domain of EHD2, which facilitates canonical EHD protein interactions, was not required to direct overexpressed EHD2 to the cell surface. On the other hand, several lines of evidence indicate that the plasma membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) plays a crucial role in regulating EHD2 subcellular localization. Pharmacologic perturbation of PIP2 metabolism altered PIP2 plasma membrane distribution (as assessed by confocal microscopy), and caused EHD2 to redistribute away from the plasma membrane. Furthermore, overexpressed EHD2 localized to PIP2-enriched vacuoles generated by active Arf6. Finally, we show that although cytochalasin D caused actin microfilaments to collapse, EHD2 was nevertheless maintained at the plasma membrane. Intriguingly, cytochalasin D induced relocalization of both PIP2 and EHD2 to actin aggregates, supporting a role of PIP2 in controlling EHD2 subcellular localization. Altogether, these studies emphasize the significance of membrane lipid composition for EHD2 subcellular distribution and offer new insights into the regulation of this important endocytic protein.

Publication types

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

MeSH terms

  • ADP-Ribosylation Factor 6
  • ADP-Ribosylation Factors / genetics
  • ADP-Ribosylation Factors / metabolism
  • Actin Cytoskeleton / genetics
  • Actin Cytoskeleton / metabolism
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Membrane / chemistry
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism*
  • Cell Membrane / ultrastructure
  • Cytochalasin D / pharmacology
  • Gene Expression
  • HeLa Cells
  • Humans
  • Microscopy, Confocal
  • Phosphatidylinositol 4,5-Diphosphate / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein Transport
  • Vacuoles / chemistry
  • Vacuoles / drug effects

Substances

  • ADP-Ribosylation Factor 6
  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • EHBP1 protein, human
  • EHD2 protein, human
  • PACSIN2 protein, human
  • Phosphatidylinositol 4,5-Diphosphate
  • Cytochalasin D
  • ADP-Ribosylation Factors
  • ARF6 protein, human