| 1991 |
Rab4p is associated with early endosomes involved in transferrin-receptor recycling; ~70% of rab4p co-fractionates with early endosomes and endocytic vesicles containing 125I-labeled transferrin by free-flow electrophoresis and Percoll density-gradient centrifugation, and localizes to transferrin-receptor-containing early endosomes by immunofluorescence. |
Subcellular fractionation (free-flow electrophoresis, Percoll density-gradient centrifugation), immunofluorescence, immunoblotting |
Proceedings of the National Academy of Sciences of the United States of America |
High |
1906178
|
| 1992 |
Overexpression of wild-type rab4 causes redistribution of transferrin receptors from endosomes to the plasma membrane, blocks iron discharge by preventing delivery of transferrin to acidic early endosomes, and accumulates transferrin in non-acidic vesicles/tubules, establishing rab4 as a regulator of an early sorting event on the endocytic/recycling pathway. |
Stable cell lines overexpressing wild-type or mutant rab4; measurement of endocytosis, lysosomal transport, and recycling; transferrin trafficking assays |
Cell |
High |
1516131
|
| 1992 |
Rab4 is phosphorylated at Ser196 by p34cdc2 kinase during mitosis, which causes its reversible translocation from endosome membranes to the cytosol; mutation of Ser196 blocks phosphorylation and prevents cytosolic accumulation, without affecting C-terminal isoprenylation or carboxymethylation. |
In vitro phosphorylation by recombinant p34cdc2 kinase; stable transfection of CHO cells with Ser196 mutants; cell-cycle analysis |
The EMBO journal |
High |
1425574
|
| 1993 |
Rab4 undergoes isoprenylation followed by proteolytic processing and carboxymethylation for membrane association; the isoprenylated intermediate of rab4 (unlike rab5) is carboxymethylated, and full post-translational processing is required for membrane targeting. |
Metabolic labeling with [35S]methionine and [3H]mevalonolactone; protease inhibitor treatment; Triton X-114 partitioning; subcellular fractionation |
Archives of biochemistry and biophysics |
Medium |
8346922
|
| 1994 |
Rab4 is phosphorylated in vitro by insulin-activated ERK1 on Ser196 in the C-terminus of the molecule, suggesting ERK1-mediated phosphorylation contributes to insulin-induced movement of Rab4 from GLUT4-containing vesicles to the cytosol in adipocytes. |
In vitro phosphorylation assay with immunopurified ERK1 from insulin-stimulated 3T3-L1 adipocytes; phosphopeptide mapping |
European journal of biochemistry |
Medium |
8112321
|
| 1996 |
Rab4 and Rab7 define non-overlapping endosomal compartments: immunoisolated NHRab4-positive vesicles contain internalized transferrin but are devoid of Rab7, establishing that Rab4 marks an early endosomal station distinct from late endosomes. |
Immunoisolation of endocytic vesicles using epitope-tagged Rab4; immunoblotting for Rab7; confocal immunofluorescence |
The Journal of biological chemistry |
High |
8910576
|
| 1996 |
Rab4-positive early endosomes and Rab4-negative pericentriolar recycling vesicles are biochemically distinct: transferrin receptor traverses first through Rab4/cellubrevin double-positive early endosomes, then accumulates in Rab4-negative, cellubrevin-positive recycling vesicles; nocodazole disrupts location but not identity of these compartments. |
Triple-label immunofluorescence confocal microscopy; nocodazole and brefeldin A treatments |
Proceedings of the National Academy of Sciences of the United States of America |
High |
8790369
|
| 1996 |
Rab4 participates in the intracellular retention of GLUT4 in adipocytes under basal conditions and in insulin-stimulated GLUT4 translocation; GTP binding (but not hydrolysis) is required; the effect is specific to Rab4 (not Rab3D). |
Transient co-transfection of epitope-tagged Glut4-myc with Rab4 mutants in isolated adipocytes; quantitative surface GLUT4 measurement |
Molecular and cellular biology |
Medium |
8943343
|
| 1996 |
A synthetic peptide corresponding to the Rab4 hypervariable C-terminal domain (residues 191–210) inhibits insulin-stimulated GLUT4 translocation and glucose transport in rat adipocytes by ~50%, identifying this domain as functionally critical for exocytotic GLUT4 recruitment. |
Electroporation of synthetic peptides into rat adipocytes; glucose transport assay; GLUT4 localization |
The Journal of biological chemistry |
Medium |
8621647
|
| 1997 |
Insulin stimulates guanine nucleotide exchange on Rab4 via a wortmannin-sensitive (PI3-kinase-dependent) signaling pathway in rat adipocytes, and wortmannin also blocks insulin-induced subcellular redistribution of Rab4. |
[35S]GTPγS binding to Rab4 in permeabilized adipocytes; wortmannin pretreatment; subcellular fractionation |
The Journal of biological chemistry |
Medium |
9169411
|
| 1997 |
Microinjection of dominant-negative Rab4(N121I) or anti-Rab4 antibody inhibits insulin-induced GLUT4 translocation by ~50% and insulin-induced membrane ruffling by ~40% in 3T3-L1 adipocytes, demonstrating Rab4's GTP-binding-dependent role in both processes. |
Microinjection of Rab4 mutant proteins and antibodies into 3T3-L1 adipocytes; immunofluorescence-based GLUT4 and actin assays |
Endocrinology |
Medium |
9348225
|
| 1997 |
Cytosolic Rab4 preferentially associates with GDI-1 (over GDI-2) after insulin stimulation in 3T3-L1 adipocytes, as shown by co-precipitation; the selective Rab4-GDI-1 complex formation is not due to differential phosphorylation. |
Co-immunoprecipitation of cytosolic Rab4 with GDI isoforms from 3T3-L1 adipocytes; 32P-labeling |
Biochemistry |
Medium |
9184135
|
| 1997 |
Mitotic phosphorylation of rab4 by cdc2/cyclin B kinase in vitro prevents binding of rab4-GDI complexes to a saturable receptor on purified endosome membranes, without affecting rab4-GDI complex formation or endosomal nucleotide exchange activity; membrane phosphorylation does not dissociate bound rab4. |
In vitro reconstitution of rab4 membrane binding; in vitro phosphorylation by cdc2/cyclin B; elastase cleavage assay to isolate soluble receptor fragment |
The EMBO journal |
High |
9303294
|
| 1998 |
Rabaptin-5 contains two distinct Rab-binding domains: a C-terminal domain that binds GTP-bound Rab5 and an N-terminal domain (73-residue region) that directly binds GTP-bound Rab4, linking Rab4-mediated recycling to Rab5-mediated endocytosis. |
Yeast two-hybrid; GST pull-down; deletion mapping; recruitment assay on early endosomes |
The EMBO journal |
High |
9524117
|
| 1998 |
Expression of dominant-negative rab4(N121I) in murine B cells selectively inhibits receptor-mediated antigen processing and presentation (of antigens internalized via BCR or Fc receptors) without affecting fluid-phase endocytosis or antigen degradation, placing rab4 on the early endosome recycling pathway required for receptor-mediated antigen processing. |
Stable expression of dominant-negative rab4N121I; antigen presentation assays with receptor-bound vs. fluid-phase antigen; endocytosis/degradation assays |
The Journal of experimental medicine |
Medium |
9815254
|
| 1998 |
Exoenzyme S (ExoS) from P. aeruginosa ADP-ribosylates Rab4 on reticulocyte endocytic vesicles, and addition of ExoS to SLO-permeabilized reticulocytes highly impairs transferrin recycling, directly linking Rab4 ADP-ribosylation to inhibition of its recycling function. |
In vitro ADP-ribosylation assay with purified endocytic vesicles; transferrin recycling assay in SLO-permeabilized reticulocytes |
Biochemical and biophysical research communications |
Medium |
9514923
|
| 2000 |
Multicolor live imaging of GFP-tagged Rab4, Rab5, and Rab11 with transferrin cargo shows that endosomes are organized as dynamic mosaics of distinct, non-intermingling Rab domains: Rab5-only, Rab4+Rab5, and Rab4+Rab11. Cargo (transferrin) moves through these Rab4-containing domains in a directed fashion. |
Live-cell multicolor fluorescence imaging of GFP-Rab proteins; transferrin cargo tracking; pharmacological sensitivity assays |
The Journal of cell biology |
High |
10811830
|
| 2000 |
Rabaptin4, a novel rab4a effector, preferentially interacts with rab4a-GTP, inhibits the intrinsic GTPase activity of rab4a, and is recruited by rab4a-GTP to recycling endosomes containing cellubrevin and internalized transferrin. |
Yeast two-hybrid; co-immunoprecipitation; GTPase activity assay; immunofluorescence co-localization |
The Biochemical journal |
Medium |
10698684
|
| 2000 |
Rab4 is an essential regulator of Ca2+-induced alpha-granule exocytosis in platelets: Rab4 co-fractionates with alpha-granule markers vWF and P-selectin, and dominant-negative Rab4(S22N) inhibits vWF secretion without affecting dense-core granule secretion. |
Density-gradient fractionation of platelet organelles; dominant-negative Rab4 cell extract depletion rescue assay in permeabilized platelets; vWF and 5-HT secretion assays |
The Journal of biological chemistry |
Medium |
10938270
|
| 2000 |
Rab4 directly interacts with syntaxin 4 in a GTP-dependent manner in adipocytes; GTP-loaded Rab4 binds the cytoplasmic domain of syntaxin 4, and this interaction is inhibited by munc-18c and modulated biphasically by insulin, linking Rab4 to SNARE-mediated GLUT4 vesicle fusion. |
Co-immunoprecipitation from permeabilized adipocytes; GST pull-down with bacterially expressed proteins; GTPγS/GDPβS loading; GTPase-deficient mutant analysis |
The Journal of biological chemistry |
High |
11063739
|
| 2001 |
PDGF stimulates rapid Rab4-dependent recycling of αvβ3 integrin (but not α5β1) from early endosomes directly back to the plasma membrane, bypassing the Rab11 perinuclear recycling compartment; dominant-negative Rab4 blocks this recycling and impairs cell adhesion/spreading on vitronectin. |
Integrin trafficking assays in mouse 3T3 fibroblasts; dominant-negative Rab4 expression; cell adhesion/spreading assays; immunofluorescence |
Current biology : CB |
High |
11566097
|
| 2001 |
Dominant-negative Rab4(S22N) significantly increases early endosomal tubule length, while constitutively active Rab4(Q67L) increases vesicle numbers and shifts Rab4/VAMP2/TfR to peripheral vesicles; early endosome budding assays confirm Rab4's role in formation of synaptic-like microvesicles and recycling vesicles from early endosomes in PC12 cells. |
Immunogold electron microscopy; early endosome budding assay; overexpression of GTPase-deficient Q67L and GDP-bound S22N Rab4 mutants in PC12 cells |
Molecular biology of the cell |
Medium |
11694600
|
| 2001 |
Dominant-negative Rab4(S22N) causes significant reduction in both transferrin recycling and EGF/LDL degradation in HeLa cells, and constitutively active Rab4(Q67L) dramatically tubulates the transferrin compartment, demonstrating that Rab4 affects both recycling and degradative endosomal trafficking from the early sorting endosome. |
Expression of Rab4 dominant-negative (S22N), dominant-positive (Q67L), and wild-type in HeLa cells; quantitative ligand recycling and degradation assays |
FEBS letters |
Medium |
11322941
|
| 2001 |
Rabip4, a FYVE-finger-containing Rab4 effector, localizes to EEA1-positive early endosomes (not Rab11 or Rab7 compartments) and its co-expression with active Rab4 enlarges early endosomes and causes intracellular retention of GLUT1, identifying Rabip4 as a Rab4 effector controlling early endosomal traffic. |
Yeast two-hybrid; GST pull-down; immunofluorescence co-localization in CHO cells; GLUT1 retention assay |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
11172003
|
| 2001 |
Rab4A interacts with the central region of cytoplasmic dynein light intermediate chain-1 (LIC-1) in a GTP-dependent (nucleotide-dependent) manner, and GFP-Rab4A endosomes localize to microtubules and are redistributed by nocodazole, indicating Rab4-positive endosomes use dynein for movement. |
Yeast two-hybrid screening with Rab4A(Q67L); co-localization by fluorescence microscopy; nocodazole treatment |
Biochemical and biophysical research communications |
Medium |
11243854
|
| 2001 |
Rabip4, a Rab4 effector (via its C-terminal Rab4/Rab11-binding domain), is required for recycling; overexpression of the C-terminal region causes dramatic tubulation of the transferrin compartment and significant reduction in transferrin recycling without affecting endocytosis or degradation. |
Yeast two-hybrid; Co-immunoprecipitation; overexpression of RCP C-terminal domain in cells; quantitative transferrin recycling assay |
The Journal of biological chemistry |
Medium |
11786538
|
| 2002 |
Rab4 function in membrane recycling requires ongoing cycles of association with and dissociation from early endosomes (membrane-cytoplasm cycle): a permanently membrane-anchored chimeric Rab4 (NHrab4cbvn) is properly targeted to early endosomes and binds GTP normally, but is less efficient in transcytotic transferrin transport, demonstrating that membrane cycling is mechanistically required. |
Chimeric rab4-cellubrevin transmembrane domain construct; transport assays in MDCK cells; guanine nucleotide binding assay |
The Journal of biological chemistry |
Medium |
12036958
|
| 2002 |
In MDCK epithelial cells, Rab4 and Rab4(Q67L) redistribute transferrin receptor from basolateral to apical plasma membrane; after basolateral endocytosis at 16°C, Rab4 and Rab4(Q67L) increase apical delivery of transferrin receptor in a pathway overlapping with brefeldin A action. |
Transient transfection of MDCK cells; 125I-transferrin surface binding; immunoelectron microscopy; brefeldin A treatment |
The Journal of biological chemistry |
Medium |
11790789
|
| 2003 |
CD2AP/CMS is a Rab4-Q67L effector that interacts with both Rab4 (via yeast two-hybrid and in vitro pull-down) and c-Cbl; co-expression of Rab4-Q67L with CD2AP/CMS enlarges EEA1-positive early endosomes, and a truncated CD2AP/CMS that retains Rab4 binding but not c-Cbl binding inhibits PDGF receptor degradation. |
Yeast two-hybrid; in vitro binding; co-expression in mammalian cells; endosome morphology analysis; PDGFR degradation assay |
Traffic (Copenhagen, Denmark) |
Medium |
12559036
|
| 2003 |
Insulin stimulates Rab4 GTP loading via PI3-kinase-dependent PKC-lambda activation; Rab4 physically associates with kinesin II (KIF3) in a GTP-dependent manner (demonstrated by co-IP and in vitro GST-Rab4 pull-down); insulin stimulates KIF3 binding to microtubules via PKC-lambda, linking Rab4 to kinesin-mediated GLUT4 exocytosis. |
Photoaffinity GTP labeling; co-immunoprecipitation; GST-Rab4 pull-down; microtubule capture assay; dominant-negative PKC-lambda and Rab4 expression |
Molecular and cellular biology |
High |
12832475
|
| 2003 |
Rabip4' (an 80-kDa variant of Rabip4) binds simultaneously and specifically to GTP-bound forms of both Rab4 and Rab5 on early endosomes; dominant-negative Rabip4' reduces transferrin internalization and recycling, supporting a role as coordinator of Rab4 and Rab5 activities. |
GST pull-down; co-immunoprecipitation; dominant-negative overexpression; transferrin trafficking assay |
Molecular biology of the cell |
Medium |
14617813
|
| 2004 |
In vitro reconstitution shows that recycling vesicle formation from endosomes requires AP-1/clathrin, is rab4-dependent (but not rab5-dependent), and is regulated by rabaptin-5/rabex-5: immunodepletion of AP-1 blocks vesicle formation; rab4 depletion blocks vesicle formation; rabaptin-5/rabex-5 depletion stimulates and addition of purified protein inhibits vesicle production. |
In vitro vesicle budding assay from surface-biotinylated cells; immunodepletion of cytosolic factors; reconstitution with purified AP-1 and rabaptin-5/rabex-5 |
Molecular biology of the cell |
High |
15331762
|
| 2004 |
Elevated endosomal cholesterol in Niemann-Pick disease fibroblasts inhibits rab4-dependent (but not rab11-dependent) LacCer and transferrin recycling; in vitro extraction of rab4 from NPF endosomal fractions by GDI is severely attenuated due to cholesterol excess, and is reversed by cholesterol depletion or high-salt treatment. |
Dominant-negative Rab pull-down; quantitative fluorescent lipid recycling assay; GDI extraction assay from isolated endosomal fractions; cholesterol depletion |
Molecular biology of the cell |
Medium |
15292453
|
| 2005 |
Live dual-color TIRFM imaging of FcRn trafficking in endothelial cells shows FcRn leaves sorting endosomes in Rab4+/Rab11+ or Rab11+ compartments; Rab4 is depleted from Rab4+/Rab11+ compartments by segregation into discrete domains before the Rab11+ vesicle fuses with the plasma membrane; Rab4 is NOT involved in the final exocytic step. |
Dual-color total internal reflection fluorescence microscopy (TIRFM) and wide-field live imaging in human endothelial cells |
Molecular biology of the cell |
Medium |
15689494
|
| 2006 |
HRES-1/Rab4 overexpression reduces surface CD4 expression and targets CD4 for lysosomal degradation; dominant-negative HRES-1/Rab4(S27N) enhances CD4 surface expression, recycling, and total cellular content; pull-down studies reveal direct interaction between HRES-1/Rab4 and CD4. |
Pull-down assay; flow cytometry for surface CD4; lysosomal inhibitor experiments; dominant-negative and overexpression in Jurkat/HeLa cells |
The Journal of biological chemistry |
Medium |
16935861
|
| 2006 |
GTPase CT229 from Chlamydia trachomatis inclusion membrane interacts specifically with wild-type and constitutively active Rab4A(Q67L) but not GDP-locked Rab4A(S22N), and recruits Rab4A to the chlamydial inclusion membrane, as confirmed by yeast two-hybrid and co-localization in infected cells. |
Yeast two-hybrid screening; co-localization of DsRed-CT229 with GFP-Rab4A in HeLa cells; co-localization with CT229 at inclusion membrane in C. trachomatis-infected cells |
Infection and immunity |
Medium |
16926431
|
| 2006 |
Rab4-mediated recycling of αvβ3 integrin is required for VEGFR1-driven fibronectin polymerization and endothelial vessel branching; VEGFR1 engagement activates a Rab4A-dependent pathway transporting αvβ3 from early endosomes to plasma membrane. |
Dominant-negative Rab4A expression; fibronectin polymerization assay; organotypic angiogenesis model; integrin trafficking assay |
Traffic (Copenhagen, Denmark) |
Medium |
19302266
|
| 2007 |
NDRG1 acts as a novel Rab4a effector: it specifically interacts with constitutively active Rab4a(Q67L) but not GDP-bound Rab4a(S22N) (confirmed by in vitro reconstitution and co-IP), co-localizes with transferrin during recycling, alters kinetics of transferrin recycling, and is required for E-cadherin recycling at the TGN. |
In vitro reconstitution; co-immunoprecipitation; live-cell confocal microscopy; transferrin recycling assay; NDRG1 knockdown |
PloS one |
Medium |
17786215
|
| 2008 |
Serotonin (5-HT) transamidates (serotonylates) Rab4, stabilizing it in the GTP-bound active form; 5-HT-modified Rab4-GTP co-localizes with and binds to SERT (serotonin transporter) at the C-terminal domain (residues 616–624), retaining SERT intracellularly and decreasing its plasma membrane density. |
Serotonylation assay; co-localization and co-immunoprecipitation of Rab4-GTP with SERT; domain mapping; heterologous and platelet expression systems |
The Journal of biological chemistry |
Medium |
18227069
|
| 2009 |
mTOR activation by NO in lupus T cells upregulates HRES-1/Rab4 expression, which in turn enhances lysosomal degradation of TCRζ chain; HRES-1/Rab4 directly interacts with both CD4 and TCRζ (pull-down); siRNA knockdown of HRES-1/Rab4 and lysosomal inhibitors both augment TCRζ protein levels. |
Pull-down studies; siRNA knockdown; flow cytometry; immunoblotting; rapamycin treatment of SLE patients in vivo |
Journal of immunology |
Medium |
19201859
|
| 2009 |
TIRFM imaging reveals discrete Rab4-dependent recycling events (bright 'puffs') mediating β2-adrenergic receptor (B2AR) exocytosis; recycling event frequency is regulated by B2AR signaling via PKA phosphorylation of a specific PKA consensus site in the B2AR C-terminal tail; transferrin receptors co-packaged in the same Rab4-dependent vesicles are co-regulated. |
Total internal reflection fluorescence microscopy (TIRFM) with pH-sensitive GFP; PKA inhibition; B2AR C-terminal tail mutagenesis |
Molecular biology of the cell |
Medium |
19369423
|
| 2009 |
PKCα activity is required for PDGF-induced sorting of the PDGF β-receptor into Rab4a-positive endosomal domains and subsequent Rab4a-dependent recycling; loss of PKCα or dominant-negative Rab4a(S22N) blocks receptor recycling and increases degradation. |
PKCα knockdown (shRNAi) and myristoylated inhibitory peptides; EGFP-Rab4a dominant-negative; receptor trafficking assays in MEFs |
Molecular biology of the cell |
Medium |
19369415
|
| 2009 |
D-AKAP2 RGS domains directly interact with GTP-bound Rab4 (and Rab11), representing the first demonstration of RGS domains binding small GTPases; D-AKAP2 knockdown accelerates transferrin recycling and redistributes Rab11 and transferrin receptor to the cell periphery. |
Co-immunoprecipitation; GTP-agarose pull-down; RNAi knockdown; transferrin recycling assay |
The Journal of biological chemistry |
Medium |
19797056
|
| 2010 |
GRASP-1 is a neuron-specific Rab4 effector that segregates Rab4 from EEA1/Neep21/Rab5-positive early endosomal membranes and coordinates coupling to Rab11-labelled recycling endosomes by interacting with endosomal SNARE syntaxin 13; GRASP-1 is necessary for AMPA receptor recycling, spine morphology maintenance, and synaptic plasticity. |
Yeast two-hybrid; co-immunoprecipitation; dominant-negative expression; siRNA knockdown; electrophysiology (LTP/LTD); neuronal morphology analysis |
PLoS biology |
High |
20098723
|
| 2010 |
Corticosterone/SGK phosphorylates GDI at Ser-213, increasing GDI-Rab4 complex formation in prefrontal cortex neurons, which facilitates Rab4-mediated recycling of AMPA receptors to synaptic membranes and enhances AMPAR-mediated synaptic transmission. |
Co-immunoprecipitation; SGK phosphorylation assay; GDI Ser-213 mutagenesis; electrophysiology; surface biotinylation of AMPA receptors |
The Journal of biological chemistry |
Medium |
20051515
|
| 2012 |
TBC1D16 is a GTPase-activating protein (GAP) for Rab4A that enhances intrinsic GTP hydrolysis by Rab4A; overexpression of active (but not R494A catalytic mutant) TBC1D16 reduces transferrin receptor recycling, alters GFP-Rab4A membrane localization, and enhances EGFR degradation. |
In vitro GTPase assay (rate of GTP hydrolysis); TBC1D16 R494A inactive mutant; transferrin recycling assay; GFP-Rab4A localization; EGFR trafficking/signaling assays |
Proceedings of the National Academy of Sciences of the United States of America |
High |
23019362
|
| 2013 |
HRES-1/Rab4 overexpression depletes the mitophagy initiator Drp1 (leading to mitochondrial mass accumulation) in both human and mouse T cells; Rab4A overexpression precedes Drp1 depletion and mitochondrial accumulation in MRL/lpr lupus-prone mice; Rab geranylgeranyl transferase inhibitor 3-PEHPC increases Drp1 and reduces mitochondrial mass. |
Flow cytometry; immunoblotting; overexpression; 3-PEHPC pharmacological inhibition in mouse model; histology |
Annals of the rheumatic diseases |
Medium |
23897774
|
| 2014 |
HRES-1/Rab4 promotes formation of LC3+ autophagosomes and accumulation of mitochondria during autophagy induced by starvation or rapamycin; constitutively active Rab4(Q72L) promotes mitochondria partitioning with LC3; a C-terminally truncated native isoform Rab4(1-121) enhances autophagosome formation in resting cells; dominant-negative Rab4(S27N) abrogates these effects. |
Fluorescence microscopy co-localization of HRES-1/Rab4 with LC3 and mitochondria; multiple Rab4 isoform/mutant expression; starvation and rapamycin treatment |
PloS one |
Medium |
24404161
|
| 2014 |
Rab4 orchestrates a GTPase cascade on endosomal membranes: Rab4 recruits Arl1, which recruits BIG1/BIG2 (Arf GEFs), which in turn activate Arf1/Arf3, enabling recruitment of AP-1, AP-3, and GGA-3 sorting coats onto tubular endosomal subdomains; Arl1 depletion randomizes Rab4 distribution and blocks tubular subdomain formation. |
siRNA knockdown of pathway components; immunofluorescence; brefeldin A inhibition; epistasis analysis |
Current biology : CB |
Medium |
24835460
|
| 2014 |
RAB5A promotes RAB4- and RABENOSYN-5-dependent endo/exocytic cycles of MT1-MMP and β3 integrin, required for invadosome formation and invasive chemotaxis; Rab4 is positioned downstream of RAB5A in this prometastatic trafficking circuitry. |
Overexpression and siRNA knockdown; invadosome formation assay; ECM degradation assay; 3D invasion assay; in vivo DCIS-to-IDC conversion model |
The Journal of cell biology |
Medium |
25049275
|
| 2015 |
Rabaptin5 membrane recruitment to early endosomes requires binding to both Rab4 and Rabex5 (not Rab5); deletion of Rab5-binding domains or silencing of Rab5 does not prevent Rabaptin5 recruitment but produces giant hybrid endosomes, contradicting the canonical Rab5 positive-feedback model and indicating Rbpt5 is recruited by Rab4/Rabex5 to activate Rab5 in a feed-forward manner. |
Deletion analysis of Rabaptin5 domains; siRNA knockdown of Rab5; immunofluorescence; endosome morphology analysis |
Journal of cell science |
Medium |
26430212
|
| 2017 |
ICMT-catalyzed carboxylmethylation of RAB4A is critical for RAB4A activation, its interaction with effectors, its localization to endosomes and recycling vesicles, and consequently for RAB4A-dependent integrin β3 recycling to the plasma membrane, cell migration, and cancer metastasis. |
ICMT inhibition; RAB4A localization by immunofluorescence; integrin β3 recycling assay; in vivo invasion/metastasis assay; ICMT knockdown |
Oncogene |
Medium |
28604748
|
| 2017 |
Rab4-associated vesicles move bidirectionally in Drosophila axons with anterograde bias mediated by Kinesin-2 (KIF3A/KLP64D tail domain interaction confirmed by FKBP-FRB conjugation assay); reduced anterograde Rab4 traffic causes synaptic volume expansion, establishing that Rab4-dependent anterograde vesicular traffic is required to maintain synaptic balance. |
Live-cell axonal transport imaging; FKBP-FRB conjugation assay in rat embryonic fibroblasts; Drosophila genetic analysis; larval locomotion assay |
Cell reports |
Medium |
28273459
|
| 2018 |
Rab4A localizes to sorting endosomes in melanocytes where it forms a complex with AP-3, rabenosyn-5, and KIF3 to coordinate cargo segregation; Rab4A knockdown causes defective melanosome maturation, increased vacuolar endosomes, and mislocalization of melanosomal proteins to lysosomes, cell surface, and exosomes. |
RNAi screening; immunofluorescence; co-immunoprecipitation; electron microscopy; melanocyte-specific cargo tracking |
Journal of cell science |
Medium |
30154210
|
| 2020 |
HTT (huntingtin) is present with Rab4-containing vesicles in Drosophila axons; HTT and Rab4 move together on a unique vesicle that may also contain synaptotagmin, synaptobrevin, and Rab11, using kinesin-1 and dynein motors plus the accessory protein HIP1; polyQ-expanded HTT disrupts Rab4 motility, and excess Rab4 rescues synaptic morphology, locomotion defects, and lifespan in HD model. |
In vivo dual-color axonal imaging in Drosophila; iNeuron trafficking assay from HD patient cells; genetic rescue experiments |
Acta neuropathologica communications |
Medium |
32611447
|
| 2020 |
Agonist-activated glucagon receptors (GCGRs) traffic through Rab4a-positive recycling endosomes; deubiquitination by STAMBP and USP33 at early endosomes facilitates Rab4a-dependent GCGR recycling; a Rab4a dominant-negative blocks recycling while a ubiquitination-deficient GCGR mutant shows augmented trafficking to Rab4a endosomes. |
Endocytic colocalization assays; ubiquitination assays; siRNA knockdown of deubiquitinases; Rab4a dominant-negative; GCGR lysine-to-arginine mutant |
The Journal of biological chemistry |
Medium |
32967969
|
| 2024 |
Rab4A-directed endosome traffic controls CD98 receptor recycling; constitutively active Rab4A(Q72L) promotes CD98-dependent kynurenine production, mTOR activation, and mitochondrial metabolism, expanding CD4+ and DN T cells; Rab4A deletion in T cells or mTOR blockade reduces CD98 expression, mitochondrial mass, and attenuates glomerulonephritis in lupus-prone mice. |
Constitutively active/knockout mouse models; stable isotope metabolic tracing; CD98 surface expression assay; mTOR activation assay; renal histology |
Nature communications |
Medium |
38519468
|
| 2024 |
LRBA is recruited by Arf family members to Rab4+ endosomes (not primarily Rab11 endosomes); loss of LRBA in patient-derived fibroblasts leads to defects in the endosomal pathway, accumulation of enlarged endolysosomes, and lysosome secretion, revealing LRBA as a regulator of endosomal flow at Rab4+ endosomes. |
Immunofluorescence co-localization; patient-derived fibroblast analysis; endolysosome size/morphology quantification; lysosome secretion assay |
The Journal of cell biology |
Medium |
39325073
|