Alternative titles; symbols
HGNC Approved Gene Symbol: EEA1
Cytogenetic location: 12q22 Genomic coordinates (GRCh38) : 12:92,770,637-92,929,295 (from NCBI)
Early endosomes are cellular compartments that receive endocytosed materials and sort them for vesicular transport to late endosomes and lysosomes or for recycling to the plasma membrane.
By screening a HeLa cell expression library with autoimmune serum, Mu et al. (1995) obtained a cDNA encoding EEA1. Sequence analysis predicted that the 1,411-amino acid EEA1 protein is largely hydrophilic with short amphiphilic regions in the 15 N-terminal amino acids and in segments centered around amino acids 515 and 645. EEA1 contains an N-terminal zinc finger motif, a cys-rich C-terminal metal-binding finger, and multiple sites for N-glycosylation, phosphorylation, N-myristoylation, and for a leucine zipper structure. Northern blot analysis detected a 9.0-kb EEA1 transcript in skeletal muscle, heart, brain, lung, liver, and pancreas. Immunoblot analysis determined that EEA1 is expressed as a 180-kD protein in membrane and cytosolic fractions. Immunofluorescence microscopy showed that EEA1 colocalizes with transferrin (TF; 190000) and with RAB5 (RAB5A; 179512), which localizes in early endosomes, but not with RAB7 (602298), which localizes in late endosomes.
Murray et al. (2016) addressed the mechanism whereby a tethered vesicle comes closer towards its target membrane for fusion by reconstituting an endosomal asymmetric tethering machinery consisting of the dimeric coiled-coil protein EEA1 recruited to phosphatidylinositol 3-phosphate membranes and binding vesicles harboring RAB5. Structural analysis revealed that RAB5:GTP induces an allosteric conformational change in EEA1, from extended to flexible and collapsed. Through dynamic analysis by optical tweezers, Murray et al. (2016) confirmed that EEA1 captures a vesicle at a distance corresponding to its extended conformation, and directly measured its flexibility and the forces induced during the tethering reaction. Expression of engineered EEA1 variants defective in the conformational change induced prominent clusters of tethered vesicles in vivo. Murray et al. (2016) concluded that their results suggested a mechanism in which RAB5 induces a change in flexibility of EEA1, generating an entropic collapse force that pulls the captured vesicle towards the target membrane to initiate docking and fusion.
Using yeast 2-hybrid analysis, Simonsen et al. (1998) found that the N-terminal zinc finger and the C-terminal FYVE finger of EEA1 bind to RAB5 or RAB5-GTP and to phosphatidylinositol 3-phosphate (PtdIns(3)P), respectively. Each of these interactions stabilizes the binding of EEA1 to the endosomal membrane.
Kutateladze and Overduin (2001) determined the solution structure of the FYVE domain of EEA1 protein in the free state and compared it with the structures of the domain complexed with phosphatidylinositol 3-phosphate and mixed micelles. The multistep binding mechanism involved nonspecific insertion of a hydrophobic loop into the lipid bilayer, positioning and activating the binding pocket. Ligation of phosphatidylinositol 3-phosphate then induced a global structural change, drawing the protein termini over the bound phosphoinositide by extension of a hinge. Specific recognition of the 3-phosphate was determined indirectly and directly by 2 clusters of conserved arginines.
To determine the structural basis for selective PtdIns(3)P recognition by FYVE domains and the role of domain organization, dimerization, and quaternary structure with respect to EEA1 localization and endosome tethering, Dumas et al. (2001) characterized the binding of soluble phosphoinositides to monomeric and homodimeric constructs of EEA1 and determined the crystal structure of the homodimeric C-terminal region as a complex with the head group of PtdIns(3)P. A specific head group binding mode showed how FYVE domains selectively recognize PtdIns(3)P and discriminate against other mono- or polyphosphorylated species. The EEA1 homodimer was found to be ideally configured for multivalent membrane engagement. The simplest thermodynamic model for bivalent recognition of PtdIns(3)P in a lipid bilayer quantitatively accounted for the large amplification of the weak affinity and moderate specificity of soluble PtdIns(3)P binding to the EEA1 FYVE domain and explained why the region preceding the FYVE domain is required for localization to early endosomes.
The International Radiation Hybrid Mapping Consortium mapped the EEA1 gene to chromosome 12 (sts-X78998).
Dumas, J. J., Merithew, E., Sudharshan, E., Rajamani, D., Hayes, S., Lawe, D., Corvera, S., Lambright, D. G. Multivalent endosome targeting by homodimeric EEA1. Molec. Cell 8: 947-958, 2001. [PubMed: 11741531] [Full Text: https://doi.org/10.1016/s1097-2765(01)00385-9]
Kutateladze, T., Overduin, M. Structural mechanism of endosome docking by the FYVE domain. Science 291: 1793-1796, 2001. [PubMed: 11230696] [Full Text: https://doi.org/10.1126/science.291.5509.1793]
Mu, F.-T., Callaghan, J. M., Steele-Mortimer, O., Stenmark, H., Parton, R. G., Campbell, P. L., McCluskey, J., Yeo, J.-P., Tock, E. P. C., Toh, B.-H. EEA1, an early endosome-associated protein: EEA1 is a conserved alpha-helical peripheral membrane protein flanked by cysteine 'fingers' and contains a calmodulin-binding IQ motif. J. Biol. Chem. 270: 13503-13511, 1995. [PubMed: 7768953] [Full Text: https://doi.org/10.1074/jbc.270.22.13503]
Murray, D. H., Jahnel, M., Lauer, J., Avellaneda, M. J., Brouilly, N., Cezanne, A., Morales-Navarrete, H., Perini, E. D., Ferguson, C., Lupas, A. N., Kalaidzidis, Y., Parton, R. G., Grill, S. W., Zerial, M. An endosomal tether undergoes an entropic collapse to bring vesicles together. Nature 537: 107-111, 2016. [PubMed: 27556945] [Full Text: https://doi.org/10.1038/nature19326]
Simonsen, A., Lippe, R., Christoforidis, S., Gaullier, J.-M., Brech, A., Callaghan, J., Toh, B.-H., Murphy, C., Zerial, M., Stenmark, H. EEA1 links PI(3)K function to Rab5 regulation of endosome fusion. Nature 394: 494-498, 1998. [PubMed: 9697774] [Full Text: https://doi.org/10.1038/28879]