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TOM1 is a PI5P effector involved in the regulation of endosomal maturation

Frédéric Boal1, Rana Mansour1, Marion Gayral1

  • 1INSERM U1048, I2MC and Université Paul Sabatier, 31432 Toulouse, France.

Journal of Cell Science
|January 16, 2015
PubMed

Insights

Phosphatidylinositol 5-monophosphate (PI5P) recruits the TOM1 protein to signaling endosomes, delaying epidermal growth factor receptor (EGFR) degradation and bulk endocytosis. This reveals a new role for PI5P in regulating endosomal maturation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Phosphoinositides are key signaling lipids regulating cellular processes.
  • Phosphatidylinositol 5-monophosphate (PI5P) is involved in endosomal sorting of epidermal growth factor receptor (EGFR).

Purpose of the Study:

  • To identify new binding partners of PI5P.
  • To elucidate the role of PI5P in endosomal trafficking and EGFR degradation.

Main Methods:

  • Co-immunoprecipitation to identify PI5P binding partners.
  • Domain mapping and motif characterization for protein-protein interactions.
  • Analysis of EGFR degradation and endocytosis in cellular models.

Main Results:

  • The adaptor protein TOM1 directly binds to PI5P.
  • A specific domain and binding motif in TOM1 mediate PI5P interaction.
  • PI5P-mediated recruitment of TOM1 delays EGFR degradation and fluid-phase bulk endocytosis.

Conclusions:

  • PI5P enrichment in signaling endosomes recruits TOM1, inhibiting endosomal maturation.
  • This study identifies a novel function for PI5P in regulating endosomal system maturation.
  • The PI5P-TOM1 interaction provides new insights into EGFR trafficking and endocytosis regulation.
Keywords:
EGFRPhosphoinositidesSignaling endosomeTOM1VHS domain

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