Title

The FYVE domain of early endosome antigen 1 is required for both phosphatidylinositol 3-phosphate and Rab5 binding. Critical role of this dual interaction for endosomal localization

UMMS Affiliation

Program in Molecular Medicine

Publication Date

2-1-2000

Document Type

Article

Subjects

3T3 Cells; Amino Acid Sequence; Animals; Binding Sites; COS Cells; Endosomes; Membrane Proteins; Mice; Molecular Sequence Data; Phosphatidylinositol Phosphates; Protein Binding; Signal Transduction; Vesicular Transport Proteins; rab5 GTP-Binding Proteins

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Early endosome antigen 1 (EEA1) is 170-kDa polypeptide required for endosome fusion. EEA1 binds to both phosphtidylinositol 3-phosphate (PtdIns3P) and to Rab5-GTP in vitro, but the functional role of this dual interaction at the endosomal membrane is unclear. Here we have determined the structural features in EEA1 required for binding to these ligands. We have found that the FYVE domain is critical for both PtdIns3P and Rab5 binding. Whereas PtdIns3P binding only required the FYVE domain, Rab5 binding additionally required a 30-amino acid region directly adjacent to the FYVE domain. Microinjection of glutathione S-transferase fusion constructs into Cos cells revealed that the FYVE domain alone is insufficient for localization to cellular membranes; the upstream 30-amino acid region required for Rab5 binding must also be present for endosomal binding. The importance of Rab5 in membrane binding of EEA1 is underscored by the finding that the increased expression of wild-type Rab5 increases endosomal binding of EEA1 and decreases its dependence on PtdIns3P. Thus, the levels of Rab5 are rate-limiting for the recruitment of EEA1 to endosome membranes. PtdIns3P may play a role in modulating the Rab5 EEA1 interaction.

Rights and Permissions

Citation: J Biol Chem. 2000 Feb 4;275(5):3699-705.

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

The Journal of biological chemistry

PubMed ID

10652369