Rabaptin-5 is a direct effector of the small GTPase Rab5 in endocytic membrane fusion

Stenmark, Harald; Vitale, Gaetano; Ullrich, Oliver; Zerial, Marino

doi:10.1016/0092-8674(95)90120-5

Cited by 449 publications

(452 citation statements)

References 55 publications

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“…Initially, rabaptin-5 was identified as an interactor of rab5 (Stenmark et al, 1995) and rabex-5 as a rab5 guanine nucleotide exchange factor (Horiuchi et al, 1997). Rabaptin-5 in addition was shown to bind to rab4 and AP-1 (Vitale et al, 1998;de Renzis et al, 2002;Deneka et al, 2003).…”

Section: Rab4 and Rabaptin-5/rabex-5 Regulate The Formation Of Recyclmentioning

confidence: 99%

In Vitro Formation of Recycling Vesicles from Endosomes Requires Adaptor Protein-1/Clathrin and Is Regulated by Rab4 and the Connector Rabaptin-5

Pagano

Crottet

Prescianotto-Baschong

et al. 2004

MBoC

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The involvement of clathrin and associated adaptor proteins in receptor recycling from endosomes back to the plasma membrane is controversial. We have used an in vitro assay to identify the molecular requirements for the formation of recycling vesicles. Cells expressing the asialoglycoprotein receptor H1, a typical recycling receptor, were surface biotinylated and then allowed to endocytose for 10 min. After stripping away surface-biotin, the cells were permeabilized and the cytosol washed away. In a temperature-, cytosol-, and nucleotide-dependent manner, the formation of sealed vesicles containing biotinylated H1 could be reconstituted. Vesicle formation was strongly inhibited upon immunodepletion of adaptor protein (AP)-1, but not of AP-2 or AP-3, from the cytosol, and was restored by readdition of purified AP-1. Vesicle formation was stimulated by supplemented clathrin, but inhibited by brefeldin A, consistent with the involvement of ARF1 and a brefeldin-sensitive guanine nucleotide exchange factor. The GTPase rab4, but not rab5, was required to generate endosome-derived vesicles. Depletion of rabaptin-5/rabex-5, a known interactor of both rab4 and ␥-adaptin, stimulated and addition of the purified protein strongly inhibited vesicle production. The results indicate that recycling is mediated by AP-1/clathrin-coated vesicles and regulated by rab4 and rabaptin-5/rabex-5. INTRODUCTIONEarly endosomes are a major sorting station for proteins and membranes in eukaryotic cells (Gruenberg, 2001;Maxfield and McGraw, 2004). They receive material from the cell surface by endocytosis and from the exocytic pathway via the trans-Golgi network (TGN), and they distribute it further to late endosomes and back to the TGN and the plasma membrane. Transport receptors like the transferrin receptor, the low-density lipoprotein (LDL) receptor, and the asialoglycoprotein (ASGP) receptor cycle continuously between the plasma membrane and early endosomes (Spiess, 1990;Trowbridge et al., 1993). Receptor-positive early endosomes can be subdivided into sorting endosomes and recycling endosomes (or endocytic recycling compartment, ERC). Primary endocytic vesicles fuse to sorting endosomes where ligands dissociate from their receptors because of a reduced internal pH. The receptors exit into tubular membranes that form recycling endosomes, whereas the ligands with the main fluid volume mature to late endosomes ("geometrybased sorting"; Maxfield and McGraw, 2004). There seem to be two main recycling pathways from early endosomes to the plasma membrane: a fast one directly from sorting endosomes and a slower one via recycling endosomes (Sheff et al., 1999;Hao and Maxfield, 2000;.The mechanisms to generate endosome-derived recycling vesicles are not clear, because there are seemingly contradictory findings. In general, formation of transport vesicles between organelles of the endocytic and secretory pathways requires cytosolic coat proteins to be recruited at the membrane of the donor compartment. Among the established coat complexes, clathr...

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Section: Rab4 and Rabaptin-5/rabex-5 Regulate The Formation Of Recyclmentioning

confidence: 99%

In Vitro Formation of Recycling Vesicles from Endosomes Requires Adaptor Protein-1/Clathrin and Is Regulated by Rab4 and the Connector Rabaptin-5

Pagano

Crottet

Prescianotto-Baschong

et al. 2004

MBoC

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“…The domain can be recognized in five proteins from baker's yeast, Saccharomyces cerevisiae, and in several mammalian proteins including early endosomal autoantigen 1 (EEA1), Hrs, and SARA (Smad anchor for receptor activation) (30,38). In yeast, three of these proteins have been implicated in the regulation of endocytic trafficking events (Vps27, Fab1, and Vac1 [4]), while in mammalian cells EEA1 has been shown to regulate early endosome fusion (16,27).…”

mentioning

confidence: 99%

Endosomal Localization and Receptor Dynamics Determine Tyrosine Phosphorylation of Hepatocyte Growth Factor-Regulated Tyrosine Kinase Substrate

Urbé

Mills

Stenmark

et al. 2000

Molecular and Cellular Biology

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Hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) is a prominent substrate for activated tyrosine kinase receptors that has been proposed to play a role in endosomal membrane trafficking. The protein contains a FYVE domain, which specifically binds to the lipid phosphatidylinositol (PI) 3-phosphate (PI 3-P). We show that this interaction is required both for correct localization of the protein to endosomes that only partially coincides with early endosomal autoantigen 1 and for efficient tyrosine phosphorylation of the protein in response to epidermal growth factor stimulation. Treatment with wortmannin reveals that Hrs phosphorylation also requires PI 3-kinase activity, which is necessary to generate the PI 3-P required for localization. We have used both hypertonic media and expression of a dominant-negative form of dynamin (K44A) to inhibit endocytosis; under which conditions, receptor stimulation fails to elicit phosphorylation of Hrs. Our results provide a clear example of the coupling of a signal transduction pathway to endocytosis, from which we propose that activated receptor (or associated factor) must be delivered to the appropriate endocytic compartment in order for Hrs phosphorylation to occur.Hepatocyte growth factor (HGF)-regulated tyrosine kinase substrate (Hrs) is a prominent target for tyrosine phosphorylation following the activation of tyrosine kinase receptors (11). It was initially shown to lie downstream of the HGF (scatter factor) receptor c-met, but activation of other tyrosine kinase receptors and by cytokines such as interleukin-2 and granulocyte-macrophage colony-stimulating factor also results in phosphorylation of Hrs (1). It is localized to transferrin receptor-containing endosomes (12) and bears significant similarity (including a FYVE-finger motif and a VHS domain) to the Saccharomyces cerevisiae protein Vps27. Vps27 belongs to the class E set of Vps mutants which are defective in transport from the sorting endosome to the vacuole (2, 22). A highly related protein, Hrs-2, has been shown to interact with SNAP-25 and SNAP-23, homologous proteins which are involved in regulated exocytosis and other intracellular fusion events, respectively (3).Two proteins that bind to Hrs have been identified which have been named STAM (for signal-transducing adapter molecule) and Hrs binding protein (Hbp) (1, 31). They show 53% sequence identity, each bears an SH3 domain, and both are also tyrosine phosphorylated. In T cells, overexpression of Hrs leads to suppression of cytokine-mediated DNA synthesis, while a mutant unable to bind STAM is without effect (1). NIH 3T3 cells stably transfected with mutants of Hbp that lack the SH3 domain or the binding site for Hrs are impaired in degrading internalized platelet-derived growth factor (31). This latter result is consistent with a role for Hrs in regulating transport from early to late endosomes (or multivesicular bodies) proposed by analogy to Vps27 function in yeast.The FYVE domain is a double zinc finger domain that has been shown ...

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“…Rab5 also regulates the homotypic fusion of early endosomes. Rabaptin-5, EEA1, hVPS34/p150, and Rabenosyn-5 have been identified as Rab5 target proteins (Stenmark et al, 1995;Christoforidis et al, 1999aChristoforidis et al, , 1999bCallaghan et al, 1999). The characterization of these target proteins has revealed that Rab5 can regulate several steps through these multiple target proteins and that these target proteins act cooperatively to coordinate the various functions of Rab5 in early endocytic traffic.…”

Section: Introductionmentioning

confidence: 99%

Rabring7, a Novel Rab7 Target Protein with a RING Finger Motif

Mizuno

Kitamura

Sasaki

2003

MBoC

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Rab7, a member of the Rab family small G proteins, has been shown to regulate intracellular vesicle traffic to late endosome/lysosome and lysosome biogenesis, but the exact roles of Rab7 are still undetermined. Accumulating evidence suggests that each Rab protein has multiple target proteins that function in the exocytic/endocytic pathway. We have isolated a new Rab7 target protein, Rabring7 (Rab7-interacting RING finger protein), using a CytoTrap system. It contains an H2 type RING finger motif at the C termini. Rabring7 shows no homology with RILP, which has been reported as another Rab7 target protein. GST pull-down and coimmunoprecipitation assays demonstrate that Rabring7 specifically binds the GTP-bound form of Rab7 at the N-terminal portion. Rabring7 is found mainly in the cytosol and is recruited efficiently to late endosomes/lysosomes by the GTP-bound form of Rab7 in BHK cells. Overexpression of Rabring7 not only affects epidermal growth factor degradation but also causes the perinuclear aggregation of lysosomes, in which the accumulation of the acidotropic probe LysoTracker is remarkably enhanced. These results suggest that Rabring7 plays crucial roles as a Rab7 target protein in vesicle traffic to late endosome/lysosome and lysosome biogenesis

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Rabaptin-5 is a direct effector of the small GTPase Rab5 in endocytic membrane fusion

Cited by 449 publications

References 55 publications

In Vitro Formation of Recycling Vesicles from Endosomes Requires Adaptor Protein-1/Clathrin and Is Regulated by Rab4 and the Connector Rabaptin-5

In Vitro Formation of Recycling Vesicles from Endosomes Requires Adaptor Protein-1/Clathrin and Is Regulated by Rab4 and the Connector Rabaptin-5

Endosomal Localization and Receptor Dynamics Determine Tyrosine Phosphorylation of Hepatocyte Growth Factor-Regulated Tyrosine Kinase Substrate

Rabring7, a Novel Rab7 Target Protein with a RING Finger Motif

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