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Showing RAB9A — RAB9 is a alias.

RAB9A

Ras-related protein Rab-9A · UniProt P51151

Length
201 aa
Mass
22.8 kDa
Annotated
2026-06-10
75 papers in source corpus 33 papers cited in narrative 32 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 9/9 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

RAB9A is a late-endosomal Rab GTPase that drives retrograde recycling of mannose 6-phosphate receptors (MPRs) from late endosomes to the trans-Golgi network, a transport step required for efficient lysosomal enzyme sorting and lysosomal biogenesis (PMID:8440258, PMID:7909812). Cycling between GDP- and GTP-bound states (with defined intrinsic hydrolysis and nucleotide-exchange kinetics) governs its activity (PMID:8463223): GDI delivers prenylated Rab9-GDP to late endosomes, where an endosome-associated exchange activity converts it to the active GTP form and GDI then extracts Rab9-GDP for cytosolic recycling (PMID:8389620, PMID:8164745, PMID:8195183, PMID:7592724). On late endosomes Rab9 occupies a distinct microdomain separate from Rab7, enriched in CI-MPR, from which Rab9-positive vesicles bud and fuse with the TGN (PMID:11827983). In its GTP-bound state Rab9 recruits a set of effectors that execute transport: the cargo adaptor TIP47, whose Rab9 binding enhances its affinity for MPR cytoplasmic tails and couples cargo capture to the active GTPase, and the effector p40, which synergizes with Rab9 to stimulate transport and is anchored to membranes by PIKfyve-catalyzed phosphorylation (PMID:9230071, PMID:11359012, PMID:12032303, PMID:14530284); effector occupancy in turn stabilizes Rab9 on the membrane and dictates its localization (PMID:15456905, PMID:16769818). Additional GTP-dependent effectors connect Rab9 to other organelle pathways and the cytoskeleton: Nde1/Ndel1 tethers Rab9-positive late endosomes to the dynein motor for retrograde transport (defined by crystal structure) (PMID:34793709), while the TBC-domain proteins RUTBC1 and RUTBC2 bind Rab9A-GTP yet act as GAPs for Rab32/Rab33B and Rab34/Rab36 respectively, linking Rab9 to adjacent Rab pathways (PMID:21808068, PMID:22637480). BLOC-3 (HPS1-HPS4) is a GTP-dependent Rab9 effector, but this interaction is dispensable for melanogenesis (PMID:20048159, PMID:30837268). Distinct from its trafficking role, Rab9 mediates an ATG7/LC3-independent alternative autophagy in which a Ulk1-Rab9-Rip1-Drp1 complex, dependent on Ulk1 phosphorylation of Rab9 at Ser179, recruits trans-Golgi membranes to damaged mitochondria and is cardioprotective during ischemia (PMID:30511961). Rab9 dysfunction is mechanistically tied to Niemann-Pick type C, where cholesterol stabilizes inactive Rab9 on membranes and impairs MPR recycling (PMID:16644737). The GDP-bound state is intrinsically unstable, exposing a conformation-dependent hydrophobic degron in switch I recognized by the p97/VCP quality-control machinery, which couples Rab9a turnover to correct CI-M6PR trafficking (PMID:41628772).

Mechanistic history

Synthesis pass · year-by-year structured walk · 29 steps
  1. 1993 High

    Established Rab9 as a functionally specific, prenylation-dependent regulator of late endosome-to-TGN transport of MPRs, distinct from the co-resident Rab7.

    Evidence Cell-free transport reconstitution with prenylated recombinant Rab9, C-terminal truncation mutant, and Rab7 specificity control

    PMID:8440258

    Open questions at the time
    • Effectors mediating the transport step not yet identified
    • Mechanism of selective late-endosome targeting unresolved
  2. 1993 High

    Defined the intrinsic enzymatic parameters of Rab9, quantifying its slow GTP hydrolysis and nucleotide exchange rates as the kinetic basis for its GTPase switch.

    Evidence In vitro GTP hydrolysis and nucleotide binding kinetics with purified recombinant Rab9

    PMID:8463223

    Open questions at the time
    • No GAP or GEF identified at this stage
    • Does not connect kinetics to in vivo regulation
  3. 1993 High

    Showed Rab9 cycles through a cytosolic GDI-bound, GDP-state pool, defining how the prenylated GTPase is solubilized and recycled in a nucleotide-state-dependent manner.

    Evidence In vitro reconstitution of GDI-Rab9 complex with geranylgeranylation and membrane extraction assays

    PMID:8389620

    Open questions at the time
    • Identity of the membrane GEF not established
    • Spatial coupling of extraction to transport cycle not resolved
  4. 1994 High

    Demonstrated in living cells that Rab9 GTPase activity is required for MPR recycling and lysosomal biogenesis, validating in vitro findings physiologically.

    Evidence Dominant-negative Rab9(S21N) overexpression with pulse-chase lysosomal enzyme sorting assays

    PMID:7909812

    Open questions at the time
    • Dominant-negative may sequester shared GEFs
    • Direct effectors still unknown
  5. 1994 High

    Resolved the activation and recruitment cycle by showing late endosomes provide GEF activity that activates GDI-delivered Rab9 upon selective membrane targeting.

    Evidence In vitro reconstitution of prenylated Rab9-GDI membrane recruitment with nucleotide exchange measurement; immunodepletion/reconstitution of cytosolic GDI-Rab9

    PMID:7592724 PMID:8164745 PMID:8195183

    Open questions at the time
    • Molecular identity of the late-endosomal GEF not determined
    • Determinants of Rab9-vs-Rab7 recruitment specificity not defined
  6. 1997 High

    Identified p40 as the first GTP-preferential Rab9 effector that synergizes with Rab9 to drive transport vesicle docking.

    Evidence Yeast two-hybrid, GST pulldown, reconstituted transport assay, and antibody inhibition with recombinant p40

    PMID:9230071

    Open questions at the time
    • Membrane recruitment mechanism of p40 not yet defined
    • Structural basis of Rab9-p40 interaction unknown
  7. 2001 High

    Established the cargo-coupling mechanism: Rab9-GTP recruits TIP47 and increases its affinity for MPR tails, linking active GTPase to cargo capture and vesicle budding.

    Evidence Direct in vitro binding, TIP47-MPR affinity measurement, and Rab9-binding-site mutant rescue in cells

    PMID:11359012

    Open questions at the time
    • Coordination between TIP47 and p40 not resolved
    • Structural details of the Rab9-TIP47 interface not yet defined
  8. 2002 High

    Mapped the discrete TIP47 region required for Rab9 binding and showed it is separate from the MPR-binding domain, defining bipartite cargo-adaptor architecture.

    Evidence Site-directed mutagenesis with circular dichroism and partial proteolysis controls

    PMID:12032303

    Open questions at the time
    • Residues necessary but not sufficient — full binding determinants incomplete
  9. 2002 High

    Visualized Rab9 as a discrete late-endosome microdomain enriched in CI-MPR from which transport vesicles bud and fuse with the TGN, defining the spatial organization of the pathway.

    Evidence Live-cell and video fluorescence microscopy with GFP-Rab9 and multiple markers

    PMID:11827983

    Open questions at the time
    • Mechanism establishing the Rab9/Rab7 domain boundary unknown
    • Fusion machinery at the TGN not defined
  10. 2003 High

    Connected lipid kinase signaling to the pathway by showing PIKfyve phosphorylates the effector p40 to anchor it to membranes.

    Evidence Yeast two-hybrid, GST pulldown, co-IP, fractionation, and in vitro kinase assay with kinase-dead PIKfyve

    PMID:14530284

    Open questions at the time
    • Phosphosite on p40 not mapped
    • Direct effect on Rab9 itself not demonstrated
  11. 2004 High

    Showed effector binding reciprocally stabilizes Rab9 on membranes and defined the cellular consequences of Rab9 loss for endosome morphology and MPR sorting.

    Evidence siRNA knockdown with endosome morphology and MPR trafficking readouts

    PMID:15456905

    Open questions at the time
    • Mechanism by which TIP47 stabilizes Rab9 not biochemically defined
  12. 2006 High

    Expanded the Rab9 effector repertoire to BLOC-3 and demonstrated that effector concentration competes to determine Rab9 subcellular localization.

    Evidence Recombinant reconstitution, analytical ultracentrifugation, switch-region mapping; Rab chimera localization with quantified effector binding

    PMID:16769818 PMID:20048159

    Open questions at the time
    • Functional role of Rab9-BLOC-3 interaction not yet defined
    • How competing effectors are spatially regulated unknown
  13. 2006 High

    Provided a mechanistic link between Rab9 and Niemann-Pick type C, showing cholesterol stabilizes inactive Rab9 and impairs MPR recycling, reversible by Rab9 overexpression.

    Evidence Half-life and GDI-extraction assays, cholesterol-loaded liposome binding, NPC siRNA model, GFP-Rab9 rescue

    PMID:16644737

    Open questions at the time
    • Direct molecular interaction of cholesterol with Rab9 not structurally defined
  14. 2009 Medium

    Linked Rab9 to the cytoskeleton via vimentin and proposed a route by which lipid accumulation entraps Rab9 in NPC1 cells.

    Evidence Co-IP, PKC inhibition, vimentin phosphorylation analysis in NPC1 cells

    PMID:18681838

    Open questions at the time
    • Single-lab co-IP without structural mapping
    • Functional consequence of Rab9-vimentin binding for normal trafficking unclear
  15. 2010 Medium

    Extended Rab9-dependent late-endosomal trafficking to control of a plasma-membrane channel, TRPC6, and downstream Ca2+ entry.

    Evidence Co-IP, co-localization, dominant-negative Rab9, Ca2+ imaging

    PMID:20346379

    Open questions at the time
    • Single study
    • Direct vs indirect Rab9-TRPC6 interaction not resolved
  16. 2011 High

    Identified RUTBC1 as a Rab9A-GTP-binding TBC protein that is a GAP not for Rab9 but for Rab32/Rab33B, positioning Rab9A as an organizer linking adjacent Rab pathways at late endosomes.

    Evidence In vitro GAP substrate screen, catalytic Arg mutagenesis, co-IP, effector-binding assay

    PMID:21808068

    Open questions at the time
    • Biological significance of Rab9A-RUTBC1 coupling in cells not fully established
  17. 2011 Medium

    Defined cargo specificity of the Rab9 pathway by showing furin requires Rab9 and GCC185 for TGN retrieval whereas TGN38 does not, mapping the determinants that route cargo into the Rab9-dependent route.

    Evidence Dominant-negative Rab9, GCC185 siRNA, furin-TGN38 chimera dissection

    PMID:21693586

    Open questions at the time
    • Single-lab study
    • Sorting determinant mechanism only partially resolved
  18. 2012 High

    Identified RUTBC2 as a second Rab9A-GTP-binding TBC protein acting as a GAP for Rab34/Rab36, reinforcing Rab9A as a hub connecting distinct Rab modules.

    Evidence In vitro GAP screen, catalytic mutagenesis, co-IP, co-localization, membrane fractionation

    PMID:22637480

    Open questions at the time
    • Physiological pathway connecting Rab9A and Rab36 not defined
  19. 2013 High

    Showed in vivo (Drosophila) that Rab9 cooperates with retromer and WASH at endosomal subdomains for selective retrograde recycling, broadening its role beyond MPRs.

    Evidence Genetic loss-of-function of Rab9, Vps35, WASH; co-localization; tube-length phenotypes

    PMID:23322046

    Open questions at the time
    • Direct biochemical link between Rab9 and retromer/WASH not established
  20. 2016 Medium

    Refined the timing of Rab9/CI-MPR entry into the endosomal pathway and showed constitutively active Rab9 disperses TGN markers without blocking retrograde transport.

    Evidence Confocal live-cell imaging with Rab9Q66L and Rab5/Rab7a co-localization

    PMID:26663757

    Open questions at the time
    • Single lab
    • Mechanism of TGN marker dispersal unresolved
  21. 2017 Medium

    Implicated Rab9-dependent late-endosomal trafficking in heterologous desensitization of the α1B-adrenergic receptor.

    Evidence FRET, confocal microscopy, dominant-negative Rab9, Ca2+ quantitation, PKC inhibitors

    PMID:28082304

    Open questions at the time
    • Single study
    • Direct Rab9-receptor interaction not demonstrated
  22. 2019 High

    Established a distinct, non-canonical function for Rab9 in ATG7/LC3-independent alternative mitophagy via a Ulk1-Rab9-Rip1-Drp1 complex driven by Ser179 phosphorylation, with cardioprotective consequences.

    Evidence Co-IP, Rab9(S179A) knockin mouse, cardiac ischemia model, ATG7-deficient controls

    PMID:30511961

    Open questions at the time
    • How phospho-Rab9 recruits trans-Golgi membranes mechanistically unclear
    • Relationship to canonical Rab9 trafficking function not resolved
  23. 2019 High

    Separated the GEF and Rab9-binding functions of HPS4, demonstrating that the Rab9-BLOC-3 interaction is dispensable for melanogenesis.

    Evidence Separation-of-function HPS4 mutants, rescue in HPS4-deficient melanocytes, melanin/tyrosinase readouts

    PMID:30837268

    Open questions at the time
    • Physiological role of the Rab9-BLOC-3 interaction remains undefined
  24. 2021 High

    Determined the structural and functional basis for Rab9A coupling to retrograde dynein transport via the effector Nde1/Ndel1.

    Evidence Crystal structure of Rab9A-GTP:Nde1, interface mutagenesis, co-IP showing loss of dynein/Lis1/dynactin association

    PMID:34793709

    Open questions at the time
    • Coordination of Nde1 tethering with budding/fusion not defined
  25. 2021 Medium

    Placed Rab9 downstream of a ULK1/Atg9a cascade in inflammation-induced Golgi fragmentation in asthma.

    Evidence ULK1 KO mice, ULK1 WT/S467A overexpression, ULK1-Atg9a co-IP, phosphosite mutagenesis

    PMID:38373380

    Open questions at the time
    • Rab9-specific evidence is downstream/indirect
    • Direct Rab9 regulatory mechanism not established
  26. 2023 Medium

    Revealed roles for Rab9 in host-pathogen interactions: NDP52-Rab9 directs HBV envelopes to lysosomal degradation, while Rab9a-GTP non-canonically inhibits retromer-mediated HPV endosomal exit.

    Evidence Co-IP of NDP52-Rab9-HBV envelope with knockdown; siRNA, dominant-negative/constitutively active Rab9a, PLA, retromer interaction assays for HPV

    PMID:37703297 PMID:38114531

    Open questions at the time
    • Single-lab studies
    • Whether Rab9 directly binds viral components not resolved
  27. 2024 Medium

    Identified TMEM9 as an activator of Rab9-dependent alternative autophagy through Beclin1 engagement and Bcl-2 displacement.

    Evidence Co-IP, Bcl-2 dissociation assay, TMEM9 glycosylation mutants, autophagy flux, co-localization

    PMID:39078420

    Open questions at the time
    • Single lab
    • Direct Rab9-TMEM9 functional coupling not biochemically defined
  28. 2024 Medium

    Linked elevated RAB9 to oocyte aging, where its overexpression disrupts spindle/actin organization and triggers PINK1-PARKIN mitophagy and oxidative stress.

    Evidence Immunofluorescence localization, Rab9 gain/loss-of-function, mitochondrial and ROS assays in human and mouse oocytes

    PMID:39676221

    Open questions at the time
    • Single study
    • Causal mechanism connecting Rab9 to spindle/actin defects unresolved
  29. 2026 Medium

    Showed that the GDP-bound state of Rab9a is intrinsically unstable due to a switch-I conformation-dependent hydrophobic degron read by p97/VCP, coupling Rab9a turnover to correct CI-M6PR trafficking.

    Evidence Half-life measurement, switch-I hydrophobic-residue mutagenesis, CI-M6PR localization assay, identification of p97 as degron reader

    PMID:41628772

    Open questions at the time
    • Single lab, recent
    • Full PQC machinery beyond p97 not defined
    • How degron sensing is balanced against GDI extraction unclear

Open questions

Synthesis pass · forward-looking unresolved questions
  • How Rab9 partitions between its canonical retrograde trafficking role and its non-canonical alternative-autophagy/host-defense roles, and what GEF activates it on late endosomes, remain unresolved.
  • Molecular identity of the late-endosomal Rab9 GEF unknown
  • Switch between trafficking and alternative-autophagy effector complexes not defined
  • Structural basis of phospho-Ser179 effector recruitment unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 4 GO:0003924 GTPase activity 2
Localization
GO:0005768 endosome 4 GO:0005794 Golgi apparatus 2 GO:0005829 cytosol 2
Pathway
R-HSA-9609507 Protein localization 4 R-HSA-5653656 Vesicle-mediated transport 2 R-HSA-9612973 Autophagy 2
Partners
HPS4NDE1NDEL1P40RUTBC1RUTBC2TIP47ULK1
Complex memberships
BLOC-3 (HPS1-HPS4) effector complexUlk1-Rab9-Rip1-Drp1 alternative-autophagy complex

Evidence

Reading pass · 32 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1993 Rab9 localizes primarily to the surface of late endosomes and, when prenylated in vitro, stimulates transport of mannose 6-phosphate receptors (MPRs) from late endosomes to the trans-Golgi network (TGN) in a cell-free reconstitution assay. C-terminally truncated Rab9 (unable to be prenylated) was inactive, and Rab7 (also on late endosomes) was inactive in this assay despite efficient prenylation and GTP binding/hydrolysis. In vitro prenylation assay, cell-free transport reconstitution, subcellular localization The EMBO journal High 8440258
1993 Rab9 hydrolyzes GTP with a rate constant of 0.0052 min⁻¹ at 37°C; GDP and GTP each dissociate from Rab9 with first-order rate constants of 0.017 min⁻¹. Second-order association rate constants for GDP and GTP binding to nucleotide-free Rab9 were 1.7×10⁶ M⁻¹s⁻¹ and 1.2×10⁵ M⁻¹s⁻¹, respectively. In vitro GTP hydrolysis assay, nucleotide binding kinetics with purified recombinant Rab9 The Journal of biological chemistry High 8463223
1993 Cytosolic Rab9 exists as an equimolar complex with a GDI-like protein (~80 kDa). Complex formation requires intact Rab9 C-terminus and geranylgeranylation; monoprenylation is sufficient. Purified Rab3A-GDI can solubilize Rab9-GDP, but not Rab9-GTP, from cytoplasmic membranes, supporting a model in which GDI recycles Rab9 from target membranes after a catalytic transport cycle. In vitro reconstitution of GDI-Rab9 complex, geranylgeranylation assay, membrane extraction assay Molecular biology of the cell High 8389620
1994 Dominant-negative Rab9(S21N) expressed in living cells strongly inhibits MPR recycling to the TGN, reduces lysosomal enzyme sorting efficiency, and causes compensatory upregulation of lysosomal enzyme synthesis—demonstrating that Rab9 GTPase activity is required for MPR recycling and efficient lysosomal biogenesis in vivo. Dominant-negative mutant overexpression in cells, pulse-chase lysosomal enzyme sorting assay, fluid-phase and receptor-mediated endocytosis controls The Journal of cell biology High 7909812
1994 Selective membrane targeting of prenylated Rab9 onto late endosome membranes is reconstituted in vitro and is accompanied by endosome-triggered nucleotide exchange (GDP→GTP). This establishes that late endosomes provide a guanine nucleotide exchange activity that activates Rab9 upon membrane delivery. In vitro membrane recruitment assay with prenylated Rab9-GDI complexes, nucleotide exchange measurement Nature High 8164745
1994 GDI-bound Rab9 (Rab9-GDI complex) represents a functional cytosolic pool that supports late endosome-to-TGN transport in vitro. GDI increases the efficiency of Rab9 utilization by suppressing mistargeting; GDI itself inhibits transport by sequestering Rab9 from membranes. Rab7 and Rab9 use biochemically distinct recruitment machineries on late endosome membranes. Immunodepletion of cytosolic GDI-Rab9, reconstitution with purified Rab9-GDI, competitive inhibition experiments The Journal of biological chemistry High 7592724 8195183
1997 p40 (a 40 kDa protein) is a Rab9-GTP-preferential effector identified by yeast two-hybrid; it does not interact with Rab7 or K-Ras. Purified recombinant p40 potently stimulates MPR transport from endosomes to TGN in vitro, anti-p40 antibodies inhibit transport, and p40 shows synergy with Rab9—consistent with p40 and Rab9 acting together to drive transport vesicle docking. Yeast two-hybrid, GST pulldown, in vitro transport assay with recombinant p40, antibody inhibition The Journal of cell biology High 9230071
2001 The cargo adaptor TIP47 binds directly to GTP-bound (active) Rab9 GTPase. Rab9-GTP binding increases the affinity of TIP47 for MPR cytoplasmic domains. A functional Rab9-binding site in TIP47 is required for TIP47 stimulation of MPR transport in vivo, establishing that Rab9 recruits TIP47 onto late endosomes and couples vesicle budding to active GTPase. Direct binding assay (in vitro), TIP47-MPR affinity measurement, dominant-negative Rab9 binding-site mutant rescue in cells Science High 11359012
2002 GFP-Rab9 localizes to late endosomes and occupies a distinct microdomain from Rab7 on the same late endosome membrane; CI-MPRs are enriched in the Rab9 domain. Live-cell video microscopy shows Rab9-positive transport vesicles (not tubules) fusing with the TGN; Rab9 remains vesicle-associated until membrane fusion and is rapidly removed upon docking/fusion. Live-cell fluorescence microscopy (GFP variants), video microscopy of vesicle fusion events The Journal of cell biology High 11827983
2002 TIP47 residues 161–169 are essential (but not sufficient) for Rab9 binding. Mutation of these residues markedly decreases Rab9 binding without altering global protein folding or the ability of TIP47 to bind MPR cytoplasmic domains, demonstrating distinct binding domains for Rab9 and MPR in TIP47. Site-directed mutagenesis, binding assay, circular dichroism, partial proteolysis Proceedings of the National Academy of Sciences of the United States of America High 12032303
2003 The lipid kinase PIKfyve physically interacts with the Rab9 effector p40 via its chaperonin domain and p40's kelch repeats (determined by yeast two-hybrid, GST pulldown, and co-IP). Kinase-dead PIKfyve causes depletion of p40 from membrane fractions. PIKfyve phosphorylates p40 on serine in vitro, and this phosphorylation correlates with p40 membrane association, suggesting PIKfyve-catalyzed phosphorylation anchors p40 to membranes to facilitate late endosome-to-TGN transport. Yeast two-hybrid, GST pulldown, co-immunoprecipitation, differential centrifugation, in vitro kinase assay The Journal of biological chemistry High 14530284
2004 Rab9 depletion by siRNA decreases late endosome size, reduces multilamellar and dense-tubule-containing late endosomes/lysosomes, causes perinuclear clustering of remaining organelles, and leads to increased surface MPRs and lysosome-associated membrane protein 1, with MPR missorting to lysosomes. Rab9 stability on late endosomes requires interaction with TIP47 (its effector), revealing that effector interaction maintains Rab membrane residence. siRNA knockdown, immunofluorescence, endosome morphology analysis, MPR trafficking assay Molecular biology of the cell High 15456905
2006 BLOC-3 (HPS1-HPS4 heterodimer) interacts specifically and strongly with GTP-bound Rab9 via the HPS4 subunit engaging the switch I and II regions of Rab9, identifying BLOC-3 as a Rab9 effector. Recombinant protein co-expression in insect cells, analytical ultracentrifugation, GST pulldown interaction screen, deletion analysis The Journal of biological chemistry High 20048159
2006 TIP47 is a key determinant of Rab9 localization: changing cellular concentrations of TIP47 (a Rab9 effector) can redirect Rab5/9 and Rab1/9 chimeras from their parental Rab localizations toward late endosomes. This demonstrates that effector concentrations compete to determine Rab localization. Chimeric Rab GTPase expression, effector binding quantification, live-cell localization assay The Journal of cell biology High 16769818
2006 Cholesterol accumulation in Niemann-Pick type C (NPC) cells elevates Rab9 protein levels (1.8-fold) by reducing its turnover and stabilizes Rab9 on endosome membranes, impairing GDI-mediated extraction. Cholesterol directly stabilizes prenylated Rab9 on liposomes in proportion to cholesterol content, sequestering Rab9 in an inactive form and disrupting CI-MPR recycling. Overexpression of GFP-Rab9 reverses MPR missorting in NPC cells. Western blot, half-life assay, GDI extraction assay, cholesterol-loaded liposome binding assay, siRNA knockdown to model NPC, GFP-Rab9 rescue The Journal of biological chemistry High 16644737
2011 RUTBC1 contains a TBC domain and binds specifically to Rab9A-GTP (in vitro and in cells) but is not a GAP for Rab9A. Instead, RUTBC1 is a GAP for Rab32 and Rab33B (requiring Arg-803 as the catalytic arginine finger, consistent with a dual-finger mechanism). Rab9A binding does not influence RUTBC1 GAP activity, but RUTBC1 influences Rab32's ability to bind its effector Varp, consistent with RUTBC1 linking Rab9A and Rab32 in adjacent pathways at late endosomes. In vitro GTP hydrolysis screen of Rab substrates, site-directed mutagenesis of catalytic Arg, co-immunoprecipitation, cell extract effector-binding assay The Journal of biological chemistry High 21808068
2011 Furin transits early and late endosomes en route to the TGN and requires Rab9 and the golgin GCC185 for efficient TGN retrieval from late endosomes. TGN38 trafficking is independent of Rab9. Furin-TGN38 chimera experiments show that both the transmembrane domain and cytoplasmic tail of TGN38 are required to divert furin from the Rab9-dependent late endosome pathway to the retromer-dependent early endosome pathway; transmembrane domain length contributes to endosomal sorting. Internalization assay, dominant-negative Rab9, siRNA knockdown of GCC185, chimeric protein expression Journal of cell science Medium 21693586
2012 RUTBC2 (TBC domain protein) binds Rab9A-GTP specifically in vitro and in cells but is not a GAP for Rab9A. RUTBC2 is a GAP for Rab34 and Rab36 (highest activity toward Rab36), requiring Arg-829 for catalysis. In cells, RUTBC2 co-localizes with Rab36 and decreases membrane-associated Rab36, linking Rab9A function to Rab36 in the endosomal system. Rab substrate GAP screen in vitro, site-directed mutagenesis, co-immunoprecipitation, co-localization, membrane fractionation The Journal of biological chemistry High 22637480
2013 In Drosophila trachea, Rab9 together with retromer (Vps35) and WASH regulates selective retrograde recycling of the luminal protein Serpentine from late endosomes. Vps35, WASH, and actin filaments differentially localize to Rab9-enriched subdomains of the endosomal membrane, where Serpentine-containing vesicles bud. Loss of Rab9, Vps35, or WASH depletes luminal Serpentine at later stages (without affecting initial secretion), causing excessively elongated tubes. Genetic mutant analysis (Rab9, Vps35, WASH loss-of-function in Drosophila), immunofluorescence co-localization, tube length phenotype quantification Nature communications High 23322046
2016 Live-cell imaging shows Rab9 constitutively active mutant (Rab9Q66L) localizes predominantly to late endosomes and disperses TGN46 and CI-MPR from the Golgi, but does not block retrograde transport of CI-MPR. Rab9 and CI-MPR enter the endosomal pathway together at the early-to-late endosome transition stage (between Rab5-positive and Rab7a-positive compartments); CI-MPR-containing vesicles attach and detach within seconds from distinct endosomal domains. Confocal live-cell imaging, constitutively active mutant expression (Rab9Q66L), co-localization with Rab5/Rab7a markers Traffic Medium 26663757
2019 During myocardial ischemia, mitophagy is mediated predominantly by Rab9-associated autophagosomes rather than the canonical ATG7/LC3 conjugation system. A protein complex of Ulk1, Rab9, Rip1, and Drp1 mediates recruitment of trans-Golgi membranes to damaged mitochondria. Ulk1 phosphorylates Rab9 at Ser179; knockin of Rab9(S179A) abolishes this alternative mitophagy and exacerbates ischemic injury without affecting conventional autophagy. Co-immunoprecipitation, knockin mouse (Rab9 S179A), cardiac ischemia model, mitophagy flux assay, ATG7-deficient controls The Journal of clinical investigation High 30511961
2009 Rab9 interacts with the intermediate filament protein vimentin. In NPC1 cells, lipid accumulation inhibits PKC, causing hypophosphorylation of vimentin, which leads to vimentin aggregation and Rab9 entrapment within the aggregates, thereby disrupting late endosome function and lipid egress. Co-immunoprecipitation, PKC inhibition assay, vimentin phosphorylation analysis, Rab9-vimentin interaction assay in NPC1 cells Biology of the cell Medium 18681838
2010 Rab9 co-localizes in vesicular structures with TRPC6 and co-immunoprecipitates with TRPC6. Dominant-negative Rab9(S21N) increases TRPC6 at the plasma membrane and augments TRPC6-mediated Ca²⁺ entry upon muscarinic stimulation, demonstrating that Rab9-dependent late endosomal trafficking regulates TRPC6 surface density. Co-immunoprecipitation, confocal co-localization, dominant-negative Rab9 expression, Ca²⁺ imaging Biochimica et biophysica acta Medium 20346379
2021 Nde1 (and its paralog Ndel1) is a Rab9A effector: GTP-bound Rab9A specifically interacts with Nde1/Ndel1 to link late endosomes to the cytoplasmic dynein motor complex. Crystal structure of Rab9A-GTP bound to the Rab9-binding region of Nde1 was determined. Key interface residues verified by mutagenesis; Rab9A mutants unable to bind Nde1 failed to associate with dynein, Lis1, and dynactin, establishing Nde1 as the tether between Rab9-positive late endosomes and dynein for retrograde transport. Crystal structure determination, biochemical pulldown, mutagenesis of interface residues, co-immunoprecipitation in cells Structure High 34793709
2021 In asthma, IL-4 activates a ULK1/Atg9a/Rab9 signaling cascade: ULK1 phosphorylates Atg9a at Ser14; Atg9a is a superior upstream regulator of Rab9; and Rab9 plays a role in inflammation-induced Golgi apparatus fragmentation. Inhibition of ULK1/Atg9a/Rab9 reduces Golgi fragmentation and mitochondrial oxidative stress. ULK1 knockout mice, lentiviral overexpression of ULK1 WT and S467A mutant in Beas-2b cells, co-IP (ULK1-Atg9a), phosphorylation site mutagenesis Redox biology Medium 38373380
2023 NDP52 forms a complex with Rab9 and HBV envelope proteins and links HBV to a Rab9-dependent lysosomal degradation pathway. This process is independent of galectin-8 and ATG5. Inactivating NDP52 reduces targeting of viral envelopes to lysosomes and increases viral replication levels. Co-immunoprecipitation (NDP52-Rab9-HBV envelope), NDP52 knockdown in hepatocytes, ATG5-independent pathway controls Nature communications Medium 38114531
2023 Rab9a in its GTP-bound form inhibits (rather than promotes) retromer-mediated endosomal exit of HPV during virus entry. Rab9a knockdown impairs retromer-mediated endosome-to-Golgi transport of HPV and causes HPV accumulation in endosomes. Excess GTP-Rab9a impairs HPV entry, whereas excess GDP-Rab9a reduces L2-Rab9a association and stimulates entry—a noncanonical action opposite to Rab9a's role for cellular cargo. siRNA knockdown, dominant-negative and constitutively active Rab9a overexpression, proximity ligation assay (Rab9a-HPV), retromer interaction assay PLoS pathogens Medium 37703297
2024 TMEM9, a lysosomal transmembrane protein, interacts with Beclin1 via its Bcl-2-binding domain to activate Rab9-dependent alternative autophagy. TMEM9-Beclin1 interaction dissociates Bcl-2 from Beclin1, enabling LC3-independent, Rab9-dependent autophagosome formation. TMEM9 colocalizes with Rab9 on late endosomes/lysosomes. Multiple glycosylation of TMEM9 (required for lysosomal localization) is essential for Beclin1 binding and Rab9-dependent autophagy activation. Co-immunoprecipitation (TMEM9-Beclin1), Bcl-2 dissociation assay, TMEM9 glycosylation mutants, autophagy flux assay, co-localization Cellular and molecular life sciences Medium 39078420
2026 GDP-bound Rab9a has an extremely short half-life compared with GTP-bound Rab9a and compared with the closely related Rab7. Hydrophobic residues exposed in the switch I region of GDP-Rab9a constitute a conformation-dependent hydrophobic (CDH) degron recognized by the protein quality control (PQC) machinery including valosin-containing protein/p97. CDH degron-mutated Rab9a accumulates in cells and causes defective CI-M6PR localization; forced accumulation phenocopies PQC dysfunction. Half-life measurement, site-directed mutagenesis of switch I hydrophobic residues, CI-M6PR localization assay, identification of p97 as CDH degron reader The Journal of biological chemistry Medium 41628772
2017 Pharmacological PKC activation promotes α1B-adrenergic receptor transfer to late endosomes (Rab9-positive compartment) following early endosome transit (Rab5). Dominant-negative Rab9-GDP abolishes receptor traffic to late endosomes, alters desensitization of the calcium response, and suppresses receptor internalization, identifying Rab9-mediated late endosome trafficking as a component of heterologous adrenergic receptor desensitization. FRET (DsRed-α1B-AR / EGFP-Rab proteins), confocal microscopy, dominant-negative Rab9 expression, intracellular Ca²⁺ quantitation, PKC inhibitors Molecular pharmacology Medium 28082304
2019 HPS4 Rab32/38-GEF activity (not its Rab9-binding activity) is essential for melanogenesis in HPS4-deficient melanocytes. Re-expression of an HPS4 mutant specifically lacking Rab9-binding activity fully rescues pigmentation and tyrosinase trafficking, whereas Rab32/38-GEF-deficient HPS4 fails to rescue. This demonstrates that the Rab9-BLOC-3 interaction is dispensable for melanogenesis. Site-directed mutagenesis of HPS4 (separate Rab32/38-GEF-null and Rab9-binding-null mutants), rescue assay in melan-le HPS4-deficient melanocytes, melanin content and tyrosinase trafficking assay The Journal of biological chemistry High 30837268
2024 RAB9 protein levels increase significantly in aged (old) oocytes in humans and mice. RAB9 localizes to the meiotic spindle periphery and cortex. Rab9 overexpression disrupts spindle formation, chromosome alignment, actin cap formation, cortical actin levels, increases ROS, decreases mitochondrial membrane potential and ATP, and activates PINK1-PARKIN mitophagy. Reducing RAB9 expression in old oocytes partially improves maturation rate, reduces ROS and spindle abnormalities. Immunofluorescence (localization in oocytes), Rab9 overexpression and knockdown, mitochondrial function assays, ROS measurement, PINK1/PARKIN pathway analysis Aging cell Medium 39676221

Source papers

Stage 0 corpus · 75 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1993 Rab9 functions in transport between late endosomes and the trans Golgi network. The EMBO journal 484 8440258
1994 Lysosome biogenesis requires Rab9 function and receptor recycling from endosomes to the trans-Golgi network. The Journal of cell biology 265 7909812
2002 Visualization of Rab9-mediated vesicle transport from endosomes to the trans-Golgi in living cells. The Journal of cell biology 243 11827983
2019 An alternative mitophagy pathway mediated by Rab9 protects the heart against ischemia. The Journal of clinical investigation 230 30511961
2001 Role of Rab9 GTPase in facilitating receptor recruitment by TIP47. Science (New York, N.Y.) 201 11359012
1994 Membrane targeting of the small GTPase Rab9 is accompanied by nucleotide exchange. Nature 172 8164745
1993 Rab GDI: a solubilizing and recycling factor for rab9 protein. Molecular biology of the cell 145 8389620
2004 Rab9 GTPase regulates late endosome size and requires effector interaction for its stability. Molecular biology of the cell 136 15456905
2005 Rab9 GTPase is required for replication of human immunodeficiency virus type 1, filoviruses, and measles virus. Journal of virology 128 16140752
1997 A novel Rab9 effector required for endosome-to-TGN transport. The Journal of cell biology 119 9230071
2006 Cholesterol accumulation sequesters Rab9 and disrupts late endosome function in NPC1-deficient cells. The Journal of biological chemistry 101 16644737
2006 TIP47 is a key effector for Rab9 localization. The Journal of cell biology 83 16769818
2002 Telomerase immortalization upregulates Rab9 expression and restores LDL cholesterol egress from Niemann-Pick C1 late endosomes. Journal of lipid research 81 12576506
2013 Rab9 and retromer regulate retrograde trafficking of luminal protein required for epithelial tube length control. Nature communications 78 23322046
2012 The small GTPases Rab9A and Rab23 function at distinct steps in autophagy during Group A Streptococcus infection. Cellular microbiology 75 22452336
2010 Assembly of the biogenesis of lysosome-related organelles complex-3 (BLOC-3) and its interaction with Rab9. The Journal of biological chemistry 73 20048159
2001 Endosome to Golgi transport of ricin is independent of clathrin and of the Rab9- and Rab11-GTPases. Molecular biology of the cell 71 11452006
2005 Protein transduction of Rab9 in Niemann-Pick C cells reduces cholesterol storage. FASEB journal : official publication of the Federation of American Societies for Experimental Biology 69 15972801
1994 Rab-GDI presents functional Rab9 to the intracellular transport machinery and contributes selectivity to Rab9 membrane recruitment. The Journal of biological chemistry 69 8195183
1995 Rab7 and Rab9 are recruited onto late endosomes by biochemically distinguishable processes. The Journal of biological chemistry 63 7592724
2011 Rab9-dependent retrograde transport and endosomal sorting of the endopeptidase furin. Journal of cell science 57 21693586
2003 Active PIKfyve associates with and promotes the membrane attachment of the late endosome-to-trans-Golgi network transport factor Rab9 effector p40. The Journal of biological chemistry 56 14530284
2011 RUTBC1 protein, a Rab9A effector that activates GTP hydrolysis by Rab32 and Rab33B proteins. The Journal of biological chemistry 53 21808068
2009 Endosomal lipid accumulation in NPC1 leads to inhibition of PKC, hypophosphorylation of vimentin and Rab9 entrapment. Biology of the cell 48 18681838
2013 TIP47 is associated with the hepatitis C virus and its interaction with Rab9 is required for release of viral particles. European journal of cell biology 44 24480419
2021 Estrogen Plays a Crucial Role in Rab9-Dependent Mitochondrial Autophagy, Delaying Arterial Senescence. Journal of the American Heart Association 41 33719502
1993 Biochemical analysis of rab9, a ras-like GTPase involved in protein transport from late endosomes to the trans Golgi network. The Journal of biological chemistry 39 8463223
2016 The multiple roles of Rab9 in the endolysosomal system. Communicative & integrative biology 38 27574541
2019 Long noncoding RNA ZFAS1 promotes tumorigenesis through regulation of miR-150-5p/RAB9A in melanoma. Melanoma research 36 30889053
2008 Development of a Rab9 transgenic mouse and its ability to increase the lifespan of a murine model of Niemann-Pick type C disease. The American journal of pathology 35 19056848
2011 Cellular vacuoles induced by Mycoplasma pneumoniae CARDS toxin originate from Rab9-associated compartments. PloS one 33 21829543
2016 Spatiotemporal Resolution of Rab9 and CI-MPR Dynamics in the Endocytic Pathway. Traffic (Copenhagen, Denmark) 32 26663757
2018 Rab9-dependent autophagy is required for the IGF-IIR triggering mitophagy to eliminate damaged mitochondria. Journal of cellular physiology 31 29574782
2012 RUTBC2 protein, a Rab9A effector and GTPase-activating protein for Rab36. The Journal of biological chemistry 30 22637480
2002 Identification of residues in TIP47 essential for Rab9 binding. Proceedings of the National Academy of Sciences of the United States of America 30 12032303
2010 Involvement of Rab9 and Rab11 in the intracellular trafficking of TRPC6. Biochimica et biophysica acta 28 20346379
2019 The BLOC-3 subunit HPS4 is required for activation of Rab32/38 GTPases in melanogenesis, but its Rab9 activity is dispensable for melanogenesis. The Journal of biological chemistry 27 30837268
2009 Phylogeny and evolution of Rab7 and Rab9 proteins. BMC evolutionary biology 27 19442299
2009 Human copper transporter 1 lacking O-linked glycosylation is proteolytically cleaved in a Rab9-positive endosomal compartment. The Journal of biological chemistry 27 19684018
2002 Selective regulation of the Rab9-independent transport of ricin to the Golgi apparatus by calcium. Journal of cell science 24 12154075
2019 Ulk1/Rab9-mediated alternative mitophagy confers cardioprotection during energy stress. The Journal of clinical investigation 23 30667375
2024 IL-4 activates ULK1/Atg9a/Rab9 in asthma, NLRP3 inflammasomes, and Golgi fragmentation by increasing autophagy flux and mitochondrial oxidative stress. Redox biology 22 38373380
2021 Loss of androgen receptor promotes HCC invasion and metastasis via activating circ-LNPEP/miR-532-3p/RAB9A signal under hypoxia. Biochemical and biophysical research communications 22 33862456
1997 Cloning and mapping of human Rab7 and Rab9 cDNA sequences and identification of a Rab9 pseudogene. Genomics 21 9126495
2024 Selective induction of Rab9-dependent alternative mitophagy using a synthetic derivative of isoquinoline alleviates mitochondrial dysfunction and cognitive deficits in Alzheimer's disease models. Theranostics 19 38164158
2019 Accumulation of sphingomyelin in Niemann-Pick disease type C cells disrupts Rab9-dependent vesicular trafficking of cholesterol. Journal of cellular physiology 19 31489965
2023 NDP52 mediates an antiviral response to hepatitis B virus infection through Rab9-dependent lysosomal degradation pathway. Nature communications 18 38114531
2021 Rab9 Mediates Pancreatic Autophagy Switch From Canonical to Noncanonical, Aggravating Experimental Pancreatitis. Cellular and molecular gastroenterology and hepatology 17 34610499
2020 RAB9A Plays an Oncogenic Role in Human Liver Cancer Cells. BioMed research international 15 32420351
2017 Protein Kinase C Activation Promotes α1B-Adrenoceptor Internalization and Late Endosome Trafficking through Rab9 Interaction. Role in Heterologous Desensitization. Molecular pharmacology 14 28082304
2019 The overexpression of Rab9 promotes tumor progression regulated by XBP1 in breast cancer. OncoTargets and therapy 13 30881034
2021 Nde1 is a Rab9 effector for loading late endosomes to cytoplasmic dynein motor complex. Structure (London, England : 1993) 12 34793709
2021 Circular RNA circSIPA1L1 Contributes to Osteosarcoma Progression Through the miR-411-5p/RAB9A Signaling Pathway. Frontiers in cell and developmental biology 11 33968929
2024 TMEM9 activates Rab9-dependent alternative autophagy through interaction with Beclin1. Cellular and molecular life sciences : CMLS 10 39078420
2020 Rab9 defense against white spot syndrome virus by participation in autophagy in Marsupenaeus japonicas. Fish & shellfish immunology 9 32526284
2023 Noncanonical Rab9a action supports retromer-mediated endosomal exit of human papillomavirus during virus entry. PLoS pathogens 8 37703297
2020 Knockdown of Rab9 Suppresses the Progression of Gastric Cancer Through Regulation of Akt Signaling Pathway. Technology in cancer research & treatment 8 32301398
2000 cDNA cloning of a new member of the Ras superfamily, RAB9-like, on the human chromosome Xq22.1-q22.3 region. Journal of human genetics 8 11043518
2020 VARP and Rab9 Are Dispensable for the Rab32/BLOC-3 Dependent Salmonella Killing. Frontiers in cellular and infection microbiology 7 33392103
2018 Modulation of cis- and trans- Golgi and the Rab9A-GTPase during infection by Besnoitia besnoiti, Toxoplasma gondii and Neospora caninum. Experimental parasitology 7 29499180
2005 Purification and analysis of TIP47 function in Rab9-dependent mannose 6-phosphate receptor trafficking. Methods in enzymology 7 16473602
2023 Isoliquiritigenin regulates the circ_0002860/miR-431-5p/RAB9A axis to function as a tumor inhibitor in melanoma. The journal of venomous animals and toxins including tropical diseases 5 37020694
2021 Circ_0013359 facilitates the tumorigenicity of melanoma by regulating miR-136-5p/RAB9A axis. Open life sciences 5 34056112
2005 Analysis of potential binding of the recombinant Rab9 effector p40 to phosphoinositide-enriched synthetic liposomes. Methods in enzymology 5 16473631
2025 The Role of the Beclin1 Complex in Rab9-Dependent Alternative Autophagy. International journal of molecular sciences 3 41009712
2024 The host Rab9a/Rab32 axis is actively recruited to the Trypanosoma cruzi parasitophorous vacuole and benefits the infection cycle. Molecular microbiology 3 38193389
2024 Age-associated accumulation of RAB9 disrupts oocyte meiosis. Aging cell 3 39676221
2023 Circ_0081054 facilitates melanoma development via sponging miR-637 and regulating RAB9A. Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) 3 37231931
2004 Purification, crystallization and preliminary X-ray analysis of the GTP-binding protein Rab9 implicated in endosome-to-TGN vesicle trafficking. Acta crystallographica. Section D, Biological crystallography 2 14993700
2026 A conformation-dependent hydrophobic degron determines Rab9a-mediated vesicular trafficking. The Journal of biological chemistry 1 41628772
2026 Dehydroandrographolide succinate alleviates ulcerative colitis via regulating RAB9A/NF-κB axis-mediated macrophage polarization and remodeling the gut microbiota. Phytomedicine : international journal of phytotherapy and phytopharmacology 0 41930813
2025 Disruption of Rab9-dependent mitophagy contributes to menopause-induced sarcopenia. Experimental gerontology 0 41274424
2024 CALCOCO2/NDP52 associates with RAB9 to initiate an antiviral response to hepatitis B virus infection through a lysosomal degradation pathway. Autophagy 0 38752371
2024 Knockdown of Rab9 Recovers Defective Morphological Differentiation Induced by Chemical ER Stress Inducer or PMD-Associated PLP1 Mutant Protein in FBD-102b Cells. Pathophysiology : the official journal of the International Society for Pathophysiology 0 39311306
2023 Noncanonical Rab9a action supports endosomal exit of human papillomavirus during virus entry. bioRxiv : the preprint server for biology 0 37205481

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