The endosome fusion regulator early-endosomal autoantigen 1 (EEA1) is a dimer

Callaghan, Judy M.; Simonsen, Anne; Gaullier, Jean Michel; Toh, Ban Hock; Stenmark, Harald

doi:10.1042/0264-6021:3380539

Cited by 102 publications

(79 citation statements)

References 25 publications

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“…These filaments are not apparently composed of cytoskeletal elements, and it is interesting to speculate that this represents a tethering complex containing EEA1 that extends from the endosomal surface. This organization is intriguing in terms of the postulated size and shape of the EEA1 molecule, which may form an extended dimer of up to 80 nm in length (Callaghan et al, 1999). Our results suggest that these filaments may extend away from the endosomal membrane to capture incoming vesicles before docking and SNARE-dependent fusion.…”

Section: Eea1 Localization and Functionmentioning

confidence: 84%

EEA1, a Tethering Protein of the Early Sorting Endosome, Shows a Polarized Distribution in Hippocampal Neurons, Epithelial Cells, and Fibroblasts

Wilson

Hoop

Zorzi

et al. 2000

MBoC

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181

153

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EEA1 is an early endosomal Rab5 effector protein that has been implicated in the docking of incoming endocytic vesicles before fusion with early endosomes. Because of the presence of complex endosomal pathways in polarized and nonpolarized cells, we have examined the distribution of EEA1 in diverse cell types. Ultrastructural analysis demonstrates that EEA1 is present on a subdomain of the early sorting endosome but not on clathrin-coated vesicles, consistent with a role in providing directionality to early endosomal fusion. Furthermore, EEA1 is associated with filamentous material that extends from the cytoplasmic surface of the endosomal domain, which is also consistent with a tethering/docking role for EEA1. In polarized cells (Madin-Darby canine kidney cells and hippocampal neurons), EEA1 is present on a subset of "basolateral-type" endosomal compartments, suggesting that EEA1 regulates specific endocytic pathways. In both epithelial cells and fibroblastic cells, EEA1 and a transfected apical endosomal marker, endotubin, label distinct endosomal populations. Hence, there are at least two distinct sets of early endosomes in polarized and nonpolarized mammalian cells. EEA1 could provide specificity and directionality to fusion events occurring in a subset of these endosomes in polarized and nonpolarized cells. INTRODUCTIONAnimal cells are continuously internalizing proteins and lipids of their plasma membrane via endocytosis. The internalized surface components enter a complex and dynamic membrane system, the early endosome, which plays a vital role in sorting endocytosed proteins to different destinations in the cell (Gruenberg and Maxfield, 1995). It is now clear that the early endosome comprises at least two functionally distinct compartments or subdomains (Ghosh et al., 1994;Ghosh and Maxfield, 1995;Gruenberg and Maxfield, 1995;Ullrich et al., 1996;Zacchi et al., 1998). Markers first enter the early sorting endosome, a complex organelle with tubular and multivesicular domains, where membrane proteins destined for degradation are sorted away from those proteins, such as the transferrin receptor, that are recycled back to the plasma membrane. Recycling proteins can then enter a second subcompartment, termed the recycling endosome, which has a tubular morphology and in many cell types is located in the pericentriolar area of the cell (Yamashiro et al., 1984;Dunn et al., 1989;Ghosh and Maxfield, 1995). Further complexity is added to this picture by the finding that fibroblasts, generally regarded as nonpolarized cells, may contain two sets of early endosomes analogous to those in polarized cells (Wilson and Colton, 1997). In these studies, endotubin, a membrane protein of the apical early endosomal compartment in neonatal rat intestine (Wilson et al., 1987), was heterologously expressed in normal rat kidney (NRK) cells and shown to associate with an apparently unique early endosomal compartment. This compartment was distinct from transferrin-containing early endosomes and was relatively insensitive to brefeldi...

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Section: Eea1 Localization and Functionmentioning

confidence: 84%

EEA1, a Tethering Protein of the Early Sorting Endosome, Shows a Polarized Distribution in Hippocampal Neurons, Epithelial Cells, and Fibroblasts

Wilson

Hoop

Zorzi

et al. 2000

MBoC

Self Cite

181

153

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“…Oligomerization is a common phenomenon in the early endocytic pathway. For example, the Rab5 effectors, Rabaptin-5 and EEA-1, have been shown to form dimers (37,38). The Rab5-binding protein RIN2 comprises two parallel dimers arranged in an anti-parallel manner (39).…”

Section: Discussionmentioning

confidence: 99%

Molecular Dissection of Rab11 Binding from Coiled-Coil Formation in the Rab11-FIP2 C-Terminal Domain

et al. 2006

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The Rab11-Family Interacting Protein (Rab11-FIP) group of effector proteins contain a highly conserved region in their C-termini that bind the GTPase, Rab11. Rab11 belongs to the largest family of small GTPases and is believed to regulate vesicle docking with target membranes and vesicle fusion. The amino acid sequence of the Rab11-FIP proteins predicts coiled-coil formation in the conserved C-terminal domain. In this study on Rab11-FIP2, we found experimental evidence for the coiled-coil and then defined the minimal structured core using limited proteolysis. We also showed that the Rab11-FIP2 coiled-coil domain forms a parallel homodimer in solution using cross-linking and mutagenesis and sedimentation equilibrium experiments. Various constructs representing the Cterminal domain of Rab11-FIP2 were characterized by circular dichroism and their affinity with Rab11 measured using isothermal titration calorimetry. The longest construct was both wellstructured and bound Rab11. A construct truncated at the N-terminus was poorly structured, but retained the same affinity for binding to Rab11. Conformational changes were also demonstrated upon complex formation between Rab11 and Rab11-FIP2. A construct truncated at the C-terminus, which was the minimal coiled-coil domain defined by limited proteolysis, did not retain the ability to interact with Rab11 although it was as well-structured as the longer peptide. These data show that coiled-coil formation and Rab11 binding are separable functions of the C-terminal domain of Rab11-FIP2. The dissection of Rab11 binding from the formation of defined structure in a coiled-coil provides a potential mechanism for regulating Rab11-dependent endosomal trafficking.

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“…EEA1, one of the four proteins in which the FYVE domain was first recognized, binds to early endosomes. The FYVE domain of EEA1 is necessary, but not sufficient, for this binding (35,194). The COOH-terminal portion of EEA1 contains a coiledcoil domain and terminates in the FYVE domain.…”

Section: Fyve Domainsmentioning

confidence: 99%

Phosphoinositides in Constitutive Membrane Traffic

Roth

2004

Physiological Reviews

266

267

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Proteins that make, consume, and bind to phosphoinositides are important for constitutive membrane traffic. Different phosphoinositides are concentrated in different parts of the central vacuolar pathway, with phosphatidylinositol 4-phosphate predominate on Golgi, phosphatidylinositol 4,5-bisphosphate predominate at the plasma membrane, phosphatidylinositol 3-phosphate the major phosphoinositide on early endosomes, and phosphatidylinositol 3,5-bisphosphate found on late endocytic organelles. This spatial segregation may be the mechanism by which the direction of membrane traffic is controlled. Phosphoinositides increase the affinity of membranes for peripheral membrane proteins that function for sorting protein cargo or for the docking and fusion of transport vesicles. This implies that constitutive membrane traffic may be regulated by the mechanisms that control the activity of the enzymes that produce and consume phosphoinositides. Although the lipid kinases and phosphatases that function in constitutive membrane traffic are beginning to be identified, their regulation is poorly understood.

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The endosome fusion regulator early-endosomal autoantigen 1 (EEA1) is a dimer

Cited by 102 publications

References 25 publications

EEA1, a Tethering Protein of the Early Sorting Endosome, Shows a Polarized Distribution in Hippocampal Neurons, Epithelial Cells, and Fibroblasts

EEA1, a Tethering Protein of the Early Sorting Endosome, Shows a Polarized Distribution in Hippocampal Neurons, Epithelial Cells, and Fibroblasts

Molecular Dissection of Rab11 Binding from Coiled-Coil Formation in the Rab11-FIP2 C-Terminal Domain

Phosphoinositides in Constitutive Membrane Traffic

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