Disease relevance of EPS15

• We have characterized two t(1;11)(p32;q11) translocations which fuse the HRX gene to a novel gene, AF-1p on chromosome 1p32, in two myeloid leukemias [1].
• Establishment of a new human acute monocytic leukemia cell line TZ-1 with t(1;11)(p32;q23) and fusion gene MLL-EPS15 [2].
• Moreover, we show that internalization of PA is dynamin and Eps15 dependent, indicating that the clathrin-dependent pathway is the major route of anthrax toxin entry into the cell [3].
• When clathrin-dependent endocytosis was inhibited by overexpression of an Eps15 dominant negative mutant, the entry and growth of Chlamydia was unaltered [4].
• Expression of a dominant-negative variant of Eps15, which is specific for clathrin-dependent endocytosis, reduced HIV entry in HeLa cells by ca 95%, confirming the role of endocytosis for productive infection [5].

High impact information on EPS15

• The 1.9 A resolution crystal structure of this domain reveals a single binding site for its ligands, which include amphiphysin, Eps15, and epsin [6].
• It is concentrated together with Eps15 in presynaptic nerve terminals, which are sites specialized for the clathrin-mediated endocytosis of synaptic vesicles [7].
• Epsin is associated with clathrin coats in situ, can be co-precipitated with AP-2 and Eps15 from brain extracts, but does not co-purify with clathrin coat components in a clathrin-coated vesicle fraction [7].
• Here we investigate the function of Eps15 by characterizing an important binding partner for its region containing EH domains; this protein, epsin, is closely related to the Xenopus mitotic phosphoprotein MP90 and has a ubiquitous tissue distribution [7].
• We demonstrated coimmunoprecipitation of Eps15 with NUMB and RAB [8].

Biological context of EPS15

• Eps15 displayed a receptor-specific pattern of tyrosine phosphorylation in vivo and was able to transform NIH3T3 cells upon overexpression [9].
• The close structural similarity of human eps15 with the murine homologue is indicated by 89% and 90% identity of nucleotide and predicted amino acid sequences, respectively [9].
• An essential function of eps15 in cell growth regulation is underscored by our observation of ubiquitous expression at the transcript and the protein level in normal and malignant human cells [9].
• Internalization was unaffected by inhibitors of protein kinase C or Ca(2+) calmodulin-dependant kinase II but was significantly reduced after transfection with dominant-negative mutant cDNAs of G protein-coupled receptor kinase 2, beta-Arrestin2, Dynamin, and Eps15 (a component of clathrin-coated pits) [10].
• This motif has been found to be the core of the binding site for the EH domains of Eps15 [11].

Anatomical context of EPS15

• Employing an expression cloning approach for tyrosine kinase substrates, we have previously isolated the coding sequence for a novel putative EGFR substrate, eps15, from NIH3T3 fibroblasts [9].
• A JC virus-induced signal is required for infection of glial cells by a clathrin- and eps15-dependent pathway [12].
• We have previously shown that the protein Eps15 is constitutively associated with the plasma membrane adaptor complex, AP-2, suggesting its possible role in endocytosis [13].
• The entire COOH-terminal domain of Eps15 or a mutant form lacking all the AP-2-binding sites was fused to the green fluorescent protein (GFP), and these constructs were transiently transfected in HeLa cells [13].
• Eps15 homology domain-NPF motif interactions regulate clathrin coat assembly during synaptic vesicle recycling [14].

Associations of EPS15 with chemical compounds

• The human eps15 gene, encoding a tyrosine kinase substrate, is conserved in evolution and maps to 1p31-p32 [9].
• Eps15 has a tripartite structure comprising a NH2-terminal portion, which contains three EH domains, a central putative coiled-coil region, and a COOH-terminal domain containing multiple copies of the amino acid triplet Aspartate-Proline-Phenylalanine [15].
• A few EH domains, such as the third EH domain (EH(3)) of human Eps15, prefer to bind Phe-Trp (FW) sequences [16].
• Using a polyglutamine (polyQ) disease model, we found that both endogenous PLIC-1 and EPS15 localize to perinuclear aggresomes, and that polyQ enhances their in vivo interaction [17].
• A regulated interaction with the UIM protein Eps15 implicates parkin in EGF receptor trafficking and PI(3)K-Akt signalling [18].
• Expression of the coiled-coil domain is sufficient to displace the wild-type Eps15 protein complex from Met, resulting in loss of tyrosine phosphorylation of Eps15 [19].

Physical interactions of EPS15

• Using glutathione-S-transferase pull-down experiments, we show that the first ubiquitin-interacting motif of Eps15 (UIM1) interacts directly with the UBL domain of ubiquilin, whereas it does not bind to ubiquitinated proteins [20].
• Using a truncated EGF receptor mutant, we demonstrate that the regulatory domain of the cytoplasmic tail of the EGF receptor is essential for the binding of Eps15 [21].
• Furthermore, recovery of the cells resulted in re-establishment of ubiquitination of both the EGF receptor and Eps15 and coincided with restoration of internalization of those receptors that had bound EGF in the presence of H2O2 [22].

Enzymatic interactions of EPS15

• In contrast, eps15 was phosphorylated by Dc 123 and Dc 165 EGF receptor mutants but not by Dc 196 and Dc 214 mutants [23].
• A longer EGF receptor deletion mutant, Dc 214, lacking all five autophosphorylation sites, was unable to phosphorylate eps15 but phosphorylated eps8 13-fold more than the wild-type receptor [23].

Co-localisations of EPS15

• Intersectin 2 isoforms show a subcellular distribution similar to other components of the endocytic machinery and co-localize with Eps15 [24].
• Hawryluk et al. demonstrate that epsin and Eps15 consistently co-localize with clathrin but never with caveolin [25].

Regulatory relationships of EPS15

• Overexpression of the fusion protein containing the entire COOH-terminal domain of Eps15 strongly inhibited endocytosis of transferrin, whereas the fusion protein in which the AP-2-binding sites had been deleted had no effect [13].
• Recently, we demonstrated that hydrogen peroxide (H2O2) inhibits the internalization of the epidermal growth factor (EGF) receptor and the EGF-induced mono-ubiquitination of EGF receptor pathway substrate clone #15 (Eps15) in fibroblasts [22].
• Both EP3.I and EP3.f internalized with beta-arrestin and internalization were blocked by a dominant negative form of Eps15, a clathrin-associated protein [26].

Other interactions of EPS15

• Furthermore, we report that synaptojanin-170, an alternatively spliced isoform of synaptojanin 1, binds Eps15, a clathrin coat-associated protein [11].
• Eps15 and its related protein Eps15R are key components of the clathrin-mediated endocytic pathway [20].
• Finally, we show that the recruitment of Eps15 into ubiquilin-positive aggregates is UIM dependent [20].
• Our data indicate that AF-1p defines another class of genes fused to HRX in 11q23 abnormalities [1].
• We have also defined the binding sites for Eps15 on squid AP180 [14].

Analytical, diagnostic and therapeutic context of EPS15

• EH is a recently identified protein-protein interaction domain found in the signal transducers Eps15 and Eps15R and several other proteins of yeast nematode [8].
• Fluorescence in situ hybridization and reverse transcription-polymerase chain reaction analyses revealed MLL-EPS15 fusion transcript and protein [2].
• Immunoprecipitation/immunoblotting experiments also demonstrated an association between EAST and eps15, an EGFR substrate associated with clathrin-coated pits and vesicles, which is essential in the endocytotic pathway [27].
• With microcapillary liquid chromatography and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF)/TOF mass spectrometry, we identified the HLA-A*0301-associated nonpolymorphic peptide KLPNSVLGR encoded by the ubiquitously expressed Eps15 homology domain-containing 2 gene as a CTL target [28].
• Finally, the effect of the Eps15 mutants on clathrin-dependent endocytosis was tested by both immunofluorescence and flow cytometry [29].

References