| 2008 |
RagB (RRAGB), as part of the heterodimeric Rag GTPase complex, binds raptor (a component of mTORC1) in an amino acid-sensitive manner and is necessary for activation of the mTORC1 pathway by amino acids. A constitutively GTP-bound RagB mutant made mTORC1 resistant to amino acid deprivation, while a GDP-bound mutant prevented amino acid stimulation of mTORC1. The Rag proteins promote intracellular localization of mTOR to a lysosomal compartment containing Rheb without directly stimulating mTORC1 kinase activity. |
Co-immunoprecipitation, dominant-active/dominant-negative GTPase mutants, subcellular localization imaging |
Science |
High |
18497260
|
| 2010 |
The Rag GTPases (including RagB/RRAGB) reside on lysosomal membranes via the Ragulator complex (encoded by MAPKSP1, ROBLD3, c11orf59), which recruits the Rags to lysosomes. Amino acids induce mTORC1 movement to lysosomal membranes where active Rag heterodimers reside. Constitutive targeting of mTORC1 to lysosomes rendered mTORC1 amino acid-insensitive and Rag/Ragulator-independent but still Rheb-dependent, placing Rag-Ragulator-mediated lysosomal translocation as the key event in amino acid signaling. |
Co-immunoprecipitation, lysosomal localization imaging, epistasis with constitutively lysosome-targeted mTORC1 |
Cell |
High |
20381137
|
| 2012 |
Ragulator functions as a guanine nucleotide exchange factor (GEF) for RagA and RagB (RRAGB), stimulating GTP loading of these GTPases in response to amino acids in a v-ATPase-dependent fashion. Two additional Ragulator components (HBXIP and C7orf59) were identified as required for mTORC1 activation by amino acids. |
In vitro GEF assay, Co-immunoprecipitation, nucleotide loading assays, genetic knockdown |
Cell |
High |
22980980
|
| 2012 |
Glutaminolysis (conversion of glutamine to α-ketoglutarate) activates mTORC1 upstream of the Rag GTPases by promoting GTP loading of RagB and lysosomal translocation of mTORC1. Inhibition of glutaminolysis prevented RagB GTP loading; constitutively active Rag heterodimer rescued mTORC1 activation in absence of glutaminolysis, placing RagB downstream of α-ketoglutarate production. |
Nucleotide loading assays for RagB, epistasis with constitutively active Rag heterodimer, lysosomal translocation imaging |
Molecular Cell |
High |
22749528
|
| 2012 |
Leucyl-tRNA synthetase (LRS) functions as a GAP (GTPase-activating protein) for Rag GTPases (including RagB/RRAGB) in response to intracellular leucine, binding directly to the Rag GTPase in an amino acid-dependent manner to activate mTORC1 signaling. |
In vitro GAP assay, Co-immunoprecipitation, mutagenesis of leucine-binding residues of LRS |
Cell |
High |
22424946
|
| 2011 |
p62/SQSTM1 binds the Rag GTPases (including RagB/RRAGB) in an amino acid-dependent manner, favors formation of the active Rag heterodimer stabilized by raptor, colocalizes with Rags at the lysosomal compartment, and is required for mTORC1 interaction with Rag GTPases and for mTORC1 translocation to the lysosome. |
Co-immunoprecipitation, co-localization imaging, amino acid-dependent interaction assays, knockdown with mTORC1 activation readouts |
Molecular Cell |
High |
21981924
|
| 2013 |
GATOR1 (composed of DEPDC5, Nprl2, Nprl3) has GTPase-activating protein (GAP) activity toward RagA and RagB (RRAGB), functioning as a negative regulator of Rag GTPases and hence mTORC1. Inactivating mutations in GATOR1 components in human cancers cause mTORC1 hyperactivation and amino acid insensitivity. |
In vitro GAP assay, cancer cell line GATOR1 knockdown, amino acid starvation epistasis, mutant analysis |
Science |
High |
23723238
|
| 2000 |
RagC and RagD were identified as novel GTP-binding proteins that interact with RagA and RagB (RRAGB) via their C-terminal regions (containing a leucine zipper and coiled-coil structure). RagC/D associated with both GDP- and GTP-bound forms of RagA. RagC and RagD changed their subcellular localization depending on the nucleotide-bound state of RagA, establishing the RagA/B–RagC/D heterodimer paradigm. |
Yeast two-hybrid, GST pulldown, radiolabeled GTP/GDP binding assay, subcellular localization studies |
Journal of Biological Chemistry |
High |
11073942
|
| 2013 |
Folliculin (FLCN) is recruited to lysosomal surfaces upon amino acid depletion and directly binds RagA/B (including RRAGB) via its GTPase domain, and together with FNIP1 promotes amino acid-dependent mTORC1 recruitment to lysosomes via Rag GTPases. |
Co-immunoprecipitation, lysosomal localization imaging, amino acid starvation/stimulation assays, FLCN knockout/knockdown |
Journal of Cell Biology |
High |
24081491
|
| 2014 |
Sestrins bind the heterodimeric RagA/B–RagC/D GTPases and function as guanine nucleotide dissociation inhibitors (GDIs) for RagA/B (including RRAGB), inhibiting amino acid-induced Rag guanine nucleotide exchange and mTORC1 lysosomal translocation. A conserved GDI motif is required; its mutation creates dominant-negative Sestrin rendering mTORC1 insensitive to amino acid deprivation. |
Co-immunoprecipitation, in vitro GDI assay, mutagenesis of GDI motif, cell-permeable peptide inhibition, mouse knockout |
Cell |
High |
25259925
|
| 2015 |
SLC38A9, a lysosomal transmembrane amino acid transporter, interacts with Rag GTPases (including RRAGB) and Ragulator in an amino acid-sensitive manner, transporting arginine with high Km. Loss of SLC38A9 represses mTORC1 activation by amino acids (particularly arginine); overexpression of its Ragulator-binding domain renders mTORC1 insensitive to amino acid starvation but not to Rag activity, placing SLC38A9 upstream of the Rag GTPases. |
Co-immunoprecipitation, amino acid transport assays, lysosomal localization imaging, loss-of-function and gain-of-function genetic epistasis |
Science |
High |
25561175 25567906
|
| 2017 |
SZT2 recruits a fraction of GATOR1 and GATOR2 to form a SZT2-orchestrated GATOR (SOG) complex essential for GATOR- and Sestrin-dependent nutrient sensing and mTORC1 regulation via Rag GTPases (including RRAGB). SZT2 deficiency causes constitutive mTORC1 signaling under nutrient deprivation; lysosomal localization of SOG is required for its function. |
Co-immunoprecipitation, lysosomal localization, genetic knockout mouse, epistasis with GATOR1/GATOR2 overexpression |
Nature |
High |
28199315
|
| 2018 |
TRIM37 interacts with mTOR and RRAGB, enhances the mTOR–RRAGB interaction, and promotes lysosomal localization of mTOR, thereby activating amino acid-stimulated mTORC1 signaling. Loss of TRIM37 reduces TFEB phosphorylation, causing its nuclear translocation and transcriptional activation of lysosome biogenesis and autophagy genes. |
Co-immunoprecipitation, lysosomal localization imaging, TRIM37 knockdown/knockout, TFEB phosphorylation and nuclear translocation assays |
Autophagy |
Medium |
29940807
|
| 2022 |
NUFIP2 contributes to mTOR inactivation (via the Ragulator-RRAGA-RRAGB complex) together with LGALS8 (galectin-8) at the lysosome following lysosomal damage. GABARAPs interact directly with NUFIP2 and are required (via Atg8ylation) for NUFIP2 recruitment to damaged lysosomes, where it inhibits the Rag GTPase complex. |
Proteomic studies of damaged lysosomes, Co-immunoprecipitation, lysosome immunopurification (LysoIP), mTOR activity assays, GABARAP knockout |
Autophagy |
Medium |
36394332
|
| 2022 |
circEXOC6B (a circular RNA) inhibits the heterodimer formation of RRAGB by directly binding to it, thereby suppressing mTORC1 pathway activity. HIF1A transcriptionally upregulates RRAGB by binding to its promoter, creating a HIF1A-RRAGB-mTORC1 positive feedback loop in colorectal cancer that circEXOC6B can interrupt. |
RNA pull-down, RNA-binding protein immunoprecipitation, Co-immunoprecipitation, chromatin immunoprecipitation, dual-luciferase assay, in vivo xenograft |
Molecular Cancer |
Medium |
35739524
|
| 2023 |
RRAGB overexpression in glioblastoma cells reduces proliferation, migration, and invasion and induces G0/G1 cell cycle arrest. RRAGB upregulation decreases expression of PI3K, phosphorylated AKT, mTOR, and S6K; restoring AKT activation rescues GBM cell proliferative and invasive properties, indicating RRAGB suppresses GBM progression partly through blockade of the PI3K/AKT signaling axis. |
RRAGB overexpression in GBM cell lines, western blot for PI3K/AKT/mTOR/S6K, AKT activator rescue experiment, xenograft and orthotopic mouse models |
Biochemical and Biophysical Research Communications |
Medium |
37517217
|
| 2024 |
RRAGB is a target of miR-21-3p in endothelial progenitor cells (EPCs); overexpression of RRAGB activates the mTOR pathway, inhibits autophagic activity, and impairs EPC proliferation, migration, and tube formation. Berberine downregulates RRAGB through upregulation of miR-21-3p, restoring EPC function and promoting wound healing. |
Luciferase reporter assay (miR-21-3p/RRAGB targeting), RRAGB overexpression in EPCs, western blot for mTOR/autophagy markers, EPC functional assays, DVT mouse model |
Regenerative Therapy |
Low |
39100534
|
| 2025 |
CircMRP4 acts as a sponge for miR-499-5p, leading to upregulation of RRAGB and consequent activation of mTORC1/P70S6K signaling in podocytes under high glucose conditions, promoting podocyte apoptosis and inflammation in diabetic kidney disease. |
Dual-luciferase reporter, RNA immunoprecipitation, RNA pull-down, RRAGB expression/knockdown, mTORC1/P70S6K western blot, in vivo DKD mouse model |
Cellular Signalling |
Low |
39842531
|