| 1993 |
A novel 37-kDa palmitoyl-protein thioesterase purified from bovine brain cytosol enzymatically removes palmitate from H-Ras. The thioesterase recognizes H-Ras only in its native conformation (bound to Mg2+ and guanine nucleotide), and it is sensitive to diethyl pyrocarbonate but insensitive to PMSF and NEM. Palmitoylated alpha subunits of heterotrimeric G proteins are also substrates. |
Enzyme purification to homogeneity, in vitro thioesterase assay with [3H]palmitate-labeled H-Ras produced in baculovirus, chemical inhibitor profiling |
The Journal of biological chemistry |
High |
7901201
|
| 1998 |
H-Ras peptide and protein substrates bind protein farnesyltransferase (FTase) as an ionized thiolate: metal coordination of the substrate cysteine sulfur by the catalytic zinc ion lowers the pKa of the thiol (pKa ~6.3), generating a bound thiolate at physiological pH. The two substrates (H-Ras CAAX peptide and FPP) bind FTase synergistically, with affinity enhanced ~70-fold in the ternary complex. |
Fluorescence binding assays, pH-dependent affinity measurements, optical absorption spectroscopy of Co2+-substituted FTase, in vitro biochemical assay |
Biochemistry |
High |
9799520
|
| 1989 |
Alternative splicing of the H-ras pre-mRNA normally suppresses p21 H-Ras expression: a negative-acting element in the last intron functions as an alternative exon; transcripts containing this exon are produced at low abundance (due to instability/defective processing) and are predicted to lack transforming potential. Mutations that prevent inclusion of this alternative exon increase H-ras expression and transforming efficiency. |
Gene reconstruction experiments, S1 nuclease analysis, mutational analysis of intronic elements, transcript identification |
Cell |
High |
2667764
|
| 1995 |
RHAMM (hyaluronan receptor) acts downstream of H-Ras in the transformation pathway: fibroblasts with a dominant suppressor mutant of RHAMM revert H-ras-transformed fibrosarcomas to a nontumorigenic, nonmetastatic phenotype, and antisense suppression of RHAMM renders fibroblasts resistant to ras transformation. Loss of functional RHAMM ablates focal adhesion kinase phosphorylation signaling within focal adhesions, preventing turnover in response to hyaluronan. |
Dominant suppressor transfection, antisense transfection, soft agar assays, in vivo tumorigenicity and metastasis assays, focal adhesion kinase phosphorylation analysis, genetic epistasis |
Cell |
High |
7541721
|
| 2002 |
H-Ras signaling through the Raf/MEK/MAPK cascade requires endocytosis and endocytic recycling, whereas K-Ras signaling does not. Dominant-interfering dynamin-K44A selectively blocked H-Ras- but not K-Ras-mediated Raf-1 activation and PC12 differentiation. Wild-type Rab5 (stimulating endocytosis and recycling) potentiated H-Ras/Raf-1 signaling, while Rab5-Q79L (endocytosis without recycling) redistributed active H-Ras to enlarged endosomes and inhibited H-Ras/Raf-1 activation. H-Ras (but not K-Ras) signaling also required PI3K activity. |
Dominant-interfering dynamin expression, Rab5 mutant overexpression, Raf-1 kinase activity assay, subcellular fractionation/localization, PC12 differentiation assay |
Molecular and cellular biology |
High |
12077341
|
| 2007 |
H-Ras enters cells via clathrin-independent endocytosis (CIE): it co-localizes with MHC class I CIE cargo and is sequestered in Arf6-Q67L vacuoles. Activated H-RasG12V induces macropinocytosis; incoming macropinosomes sequentially contain PIP2/PIP3, then PIP3/Rab5, then Rab5 alone. Arf6-Q67L traps H-Ras signaling in the PIP2/PIP3 stage, recruiting active ERK and Akt but not Rab5. |
Live fluorescence imaging, PH-domain reporters for phosphoinositides, Arf6 and Rab5 mutant expression, co-localization with CIE cargo markers |
Molecular biology of the cell |
Medium |
18094044
|
| 2009 |
H-Ras protein is degraded via beta-TrCP-mediated polyubiquitylation and proteasomal degradation. H-Ras interacts with the WD40 domain of beta-TrCP; this ubiquitylation is stimulated by Axin or APC and inhibited by Wnt3a. In vivo, intravenous Wnt3a injection in mice reduces Ras levels in intestinal tissue, establishing Wnt/beta-catenin signaling as a regulator of H-Ras stability and providing a mechanistic basis for crosstalk between Wnt and Ras-ERK pathways. |
Co-immunoprecipitation, ubiquitylation assay, proteasome inhibitor experiments, Axin/APC/Wnt3a gain- and loss-of-function, in vivo Wnt3a injection in mice |
Journal of cell science |
High |
19240121
|
| 2011 |
Metabolic stress (high palmitate/glucose) oxidizes H-Ras cysteine thiols at Cys181/184, detected by MALDI-TOF/TOF mass spectrometry, which prevents palmitoylation. Loss of palmitoylation shifts H-Ras from plasma membrane to Golgi, decreases growth factor-stimulated ERK phosphorylation (~84% reduction), and increases apoptotic signaling; these effects are prevented by wild-type but not C181/184S H-Ras, establishing oxidation of palmitoylation-site cysteines as the causal mechanism. |
MALDI-TOF/TOF mass spectrometry of Cys181/184, palmitoylation assay, subcellular fractionation, ERK phosphorylation measurement, apoptosis assay, WT vs. C181/184S mutant rescue, MnSOD overexpression |
FASEB journal |
High |
22085642
|
| 2014 |
H-Ras forms dimers on membrane surfaces via a protein-protein interface involving the switch II region (near the nucleotide binding cleft). A Y64A point mutation in switch II abolishes dimer formation. Dimerization requires the membrane surface and does not occur in solution at comparable densities; it does not require lipid anchor clustering. The 2D dimerization Kd is ~1 × 10^3 molecules/μm^2, and no higher-order oligomers are observed. |
Fluorescence correlation spectroscopy, photon counting histogram analysis, time-resolved fluorescence anisotropy, single-molecule tracking, step photobleaching, supported lipid bilayer reconstitution, site-directed mutagenesis (Y64A) |
Proceedings of the National Academy of Sciences of the United States of America |
High |
24516166
|
| 2013 |
HRas GTPase, activated downstream of EGFR signaling, is required for HCV entry into hepatocytes. Proteomic analysis showed HRas associates with tetraspanin CD81, claudin-1, integrin β1, and Rap2B in hepatocyte membranes. HRas signaling mediates lateral membrane diffusion of CD81, enabling tetraspanin receptor complex assembly necessary for HCV entry. |
Proteomic/MS analysis of HRas-associated complex, RNAi knockdown of HRas, lateral membrane diffusion assays, HCV infection assay, Co-IP |
Cell host & microbe |
High |
23498955
|
| 2004 |
In H-Ras-transformed cells, elevated MAPK activity (from H-Ras) transcriptionally induces Egr1, which in turn upregulates KLF5; KLF5 then activates cyclin D1 expression. MEK inhibitors reduce KLF5 and abolish anchorage-independent growth. siRNA knockdown of KLF5 in H-Ras-transformed cells reduces proliferation and colony formation, establishing KLF5 as a downstream mediator of H-Ras oncogenic transformation via the MEK/ERK → Egr1 → KLF5 → cyclin D1 axis. |
MEK inhibitor treatment, siRNA knockdown of KLF5 and Egr1, soft agar colony formation, proliferation assays, qRT-PCR, Western blot |
Oncogene |
Medium |
15077182
|
| 2016 |
H-ras inhibits the Hippo tumor suppressor pathway by promoting formation of inactive Mst1/Mst2 heterodimers via an ERK-dependent mechanism. Mst1/Mst2 heterodimers (mediated by SARAH domains) have much lower kinase activity than homodimers. Cells lacking Mst1 (unable to form heterodimers) are resistant to H-ras-mediated transformation and maintain active Hippo signaling. |
Co-immunoprecipitation of Mst1/Mst2 heterodimers, in vitro kinase assay comparing homo- vs. heterodimer activity, MEK inhibitor epistasis, Mst1 knockout cells, focus formation assay |
Current biology : CB |
High |
27238285
|
| 2017 |
Aurora kinase A (Aurora A) physically interacts with H-Ras through its kinase domain binding the N-terminal domain of H-Ras; Aurora A, H-Ras, and Raf-1 exist in a trimeric complex. Aurora A enhances H-Ras binding to Raf-1 and potentiates H-Ras-mediated MAPK signaling in an active H-Ras-dependent manner. |
Co-immunoprecipitation, domain-mapping pulldown assays, MAPK signaling readouts, overexpression of Aurora A with active/inactive H-Ras |
Oncotarget |
Medium |
28177880
|
| 2013 |
H-Ras transfers between cells via tunneling nanotubes (TNTs) connecting B and T cells. GFP-H-Ras diffuses freely in the TNT membrane (FRAP), and PM patches enriched in GFP-H-Ras and CD86 transfer to T-cell surfaces. Transfer is dependent on normal post-translational lipidation (palmitoylation/farnesylation) of H-Ras for plasma membrane anchorage. |
Optical tweezers cell trapping, 4D spinning-disk confocal live imaging, FRAP on TNT membranes, FACS, lipidation-defective mutant H-Ras controls |
Cell death & disease |
Medium |
23868059
|
| 2008 |
The HRAS p.Lys117Arg mutation (Costello syndrome) constitutively activates the RAS/MAPK pathway through a mechanism distinct from codon 12/13 mutations: it increases the nucleotide dissociation rate ~80-fold while retaining normal intrinsic GTP hydrolysis and GAP responsiveness. The crystal structure of HRAS p.Lys117Arg shows an altered side-chain interaction pattern that unfavorably affects nucleotide binding. |
Fluorescence nucleotide exchange/dissociation assays, GTPase activity assay, GAP-stimulated hydrolysis assay, X-ray crystallography of recombinant mutant protein |
Human mutation |
High |
17979197
|
| 2016 |
TRPML1 (encoded by MCOLN1) maintains oncogenic HRAS in signaling-competent nanoclusters at the plasma membrane by mediating cholesterol de-esterification and transport. TRPML1 inhibition disrupts cholesterol distribution, attenuates HRAS nanoclustering and plasma membrane abundance, and reduces ERK phosphorylation and proliferation selectively in HRAS-mutant cancer cells. |
MCOLN1 knockdown and pharmacological TRPML1 inhibition, cholesterol distribution assays, HRAS nanoclustering quantification, ERK phosphorylation, proliferation assays in HRAS-mutant vs. wild-type cell lines |
EMBO reports |
Medium |
30787043
|
| 2016 |
Endogenous H-Ras (mVenus-HRas knock-in) is primarily located at the plasma membrane and in small amounts in tubular recycling endosomes; EGF stimulation causes fast but transient HRas activation. EGFR endocytosis physically separates EGFR-Grb2 complexes from HRas, terminating Ras-mediated signaling, while sustained minimal ERK activation is maintained by a small pool of active EGFRs remaining at the plasma membrane. |
CRISPR/gene-editing to tag endogenous HRas with mVenus, live fluorescence imaging, subcellular colocalization, EGFR/Grb2 endosomal tracking, surface biotinylation, selective inactivation of surface EGFRs, ERK/MEK phosphorylation time courses |
Proceedings of the National Academy of Sciences of the United States of America |
High |
26858456
|
| 2019 |
Compartment-specific HRAS signaling: HRAS signaling is strongest from the cell membrane (highest kinase activation) but regulates the largest number of genes from the endoplasmic reticulum. Signaling from the Golgi apparatus activates TP53-dependent cell survival. Different subcellular locations generate distinct protein interaction profiles and kinase activation patterns that differentially regulate gene transcription. |
Compartment-targeted HRAS constructs, phosphoproteomics, protein interaction proteomics, transcriptomics, integrated network analysis |
Cell reports |
Medium |
30865897
|
| 2019 |
QPCT binds directly to HRAS and attenuates its ubiquitination, thereby increasing HRAS protein stability and activating the ERK pathway. This interaction was identified by human proteome microarray and validated by co-IP and confocal colocalization. QPCT upregulation (driven by reduced promoter methylation) confers sunitinib resistance in renal cell carcinoma via HRAS stabilization. |
Human proteome microarray, co-immunoprecipitation, confocal colocalization, ubiquitination assay, siRNA knockdown, overexpression, ERK pathway readouts |
Theranostics |
Medium |
31534544
|
| 2023 |
m6A modification at three specific sites in the HRAS 3' UTR (but not KRAS or NRAS 3' UTR) promotes H-Ras protein expression by enhancing translational elongation. This modification is regulated by the m6A eraser FTO (which removes the modification) and read by YTHDF1 (which promotes translation); YTHDF2 and YTHDF3 are not involved. Targeting HRAS m6A modification decreases cancer cell proliferation and metastasis. |
m6A sequencing, luciferase reporter assays with mutated m6A sites, YTHDF1/2/3 and FTO knockdown/overexpression, polysome profiling for translational elongation, proliferation and metastasis assays |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
36996116
|
| 2011 |
The HRAS promoter contains two G-rich elements (hras-1 and hras-2) that fold into G-quadruplex structures acting as transcriptional repressors. MAZ binds both quadruplexes; Sp1 binds only qhras-1. hnRNP A1 binds the complementary C-rich i-motif structures and unfolds them (demonstrated by FRET and CD), and is required for HRAS transcriptional activation (knockdown reduces transcript to ~44%). |
Chromatin immunoprecipitation (ChIP), EMSA, promoter mutagenesis (blocking or stabilizing quadruplexes), transcription assays, quadruplex-stabilizing ligands, RNAi knockdown |
PloS one |
Medium |
21931711
|
| 2015 |
hnRNP A1 binds the C-rich i-motif structures in the HRAS promoter GC-elements (hras-1 and hras-2), unfolds them upon binding (demonstrated by FRET and CD), and is necessary for HRAS transcriptional activation. Knockdown of hnRNP A1 reduces HRAS transcript to 44% of control. Sequestration of i-motif-binding proteins by decoy oligonucleotides significantly inhibits HRAS transcription. |
ChIP, EMSA, FRET, CD spectroscopy, shRNA knockdown of hnRNP A1, decoy oligonucleotide competition |
Scientific reports |
Medium |
26674223
|
| 2023 |
The crystal structure of the HRAS oncogene promoter i-motif (iHRAS) was solved at 1.77 Å resolution. iHRAS folds into a double hairpin forming an antiparallel i-motif dimer capped by loops; six C-C+ base pairs form each i-motif core, extended by a G-G base pair and cytosine stacking. Extensive canonical and non-canonical base pairing stabilizes the connecting region and loops. |
X-ray crystallography at 1.77 Å resolution |
Angewandte Chemie (International ed. in English) |
High |
36995904
|
| 2010 |
Endoglin (TGF-β co-receptor) inhibits H-Ras expression and its oncogenic transformation capacity. TGF-β1 increases H-Ras mRNA and protein via ALK5 and the Ras-MAPK pathway (Smad4-independent); endoglin attenuates this TGF-β1-mediated induction. Endoglin also inhibits Ras-GTP levels, phospho-MEK, and phospho-ERK in H-Ras oncogene-expressing cells, and suppresses transformation by H-RasQ61K and H-RasG12V in NIH3T3 focus formation assays. |
H-Ras promoter transactivation assay, Northern/Western blot, Ras-GTP pulldown, MEK/ERK phosphorylation, NIH3T3 focus formation assay, ALK5 inhibitor epistasis |
Carcinogenesis |
Medium |
20884686
|
| 2014 |
CIP2A physically associates with H-Ras, leading to activation of the MEK/ERK signaling pathway and promotion of epithelial-mesenchymal transition (EMT) in cervical cancer cells. The interaction was identified by pulldown/MS and validated by bilateral co-immunoprecipitation. |
Pulldown assay, mass spectrometric peptide sequencing, bilateral co-immunoprecipitation, MEK/ERK phosphorylation assay, EMT marker analysis |
Cancer letters |
Medium |
25458953
|
| 2022 |
HRAS is uniquely dependent on farnesyltransferase (FTase) for prenylation and membrane localization; NRAS and KRAS can use geranylgeranyl transferase as a bypass. Tipifarnib (FTase inhibitor) reduces HRAS processing and plasma membrane localization, decreasing GTP-bound HRAS and downstream effector pathway signaling (RAS effector pathways). This selectively inhibits growth of HRAS-mutant but not NRAS- or KRAS-mutant RMS xenografts in vivo. |
HRAS prenylation/processing assays, plasma membrane fractionation, GTP-bound HRAS (active Ras) pulldown, RAS effector pathway signaling (Western blot), 2D/3D cell growth assays, in vivo xenograft models with genomic RAS mutation stratification |
Oncogene |
High |
35459782
|
| 2022 |
Oncogenic HRAS mutations (G12S, G12A) inhibit AMPK signaling, leading to impaired mitochondrial proteostasis and defective oxidative phosphorylation. This was demonstrated in CS mouse heart/skeletal muscle, patient fibroblasts, hiPSC-derived cardiomyocytes, and zebrafish models. Pharmacological activation of mitochondrial bioenergetics restored organelle function and reduced cardiac hypertrophy. |
CS mouse model (HrasG12S), patient skin fibroblasts, hiPSC-derived cardiomyocytes, HrasG12V zebrafish model, lentiviral HRAS mutant constructs, AMPK pathway analysis, mitochondrial function assays (respiration, proteostasis), pharmacological rescue |
The Journal of clinical investigation |
High |
35230976
|
| 2021 |
Inhibition of MEK/MAPK pathway signaling with a MEK inhibitor rescues HrasG12V-induced skeletal myopathy in a Costello syndrome mouse model. Activated HrasG12V causes skeletal myopathy via inhibition of embryonic myogenesis and myofiber formation, involving hyperactivation of Ras/MAPK and PI3K/AKT pathways and significant reduction in p38 signaling. MEK inhibition rescues the myopathy both in vitro and in vivo. |
HrasG12V knock-in mouse model, muscle histomorphometry, in vitro myogenesis assays, MEK inhibitor treatment in vitro and in vivo, phosphoprotein analysis (MAPK, AKT, p38), global transcriptomics |
Disease models & mechanisms |
Medium |
34553752
|
| 2023 |
Mutant HRAS drives metastasis of head and neck cancer by suppressing the Hippo pathway and stabilizing YAP1, which transcriptionally activates AXL. Farnesyltransferase inhibitor tipifarnib activates the Hippo pathway, reduces nuclear YAP1 export, suppresses YAP1-mediated AXL expression, attenuates VEGFA/VEGFC expression, and reduces lymphovascular angiogenesis and metastasis. AXL depletion phenocopies tipifarnib in blocking invasion and metastasis. |
HRASmut human HNC cell lines, patient-derived xenografts, syngeneic mouse model, genetic (siRNA/shRNA) and pharmacological (tipifarnib) manipulation, targeted proteomics, Hippo pathway signaling analysis, in vivo metastasis assays |
Cancer research |
Medium |
36753744
|
| 1987 |
Oncogenic forms of H-ras (but not proto-oncogenic forms) completely suppress skeletal myoblast differentiation (fusion, nicotinic acetylcholine receptor and creatine kinase induction) at the level of muscle-specific mRNA accumulation, independent of effects on cell proliferation. This demonstrates H-ras mimics the differentiation-inhibitory effects of FGF and TGF-beta. |
DNA-mediated gene transfer into C2 myoblasts, myotube fusion assay, muscle-specific gene expression (Northern blot for AChR and creatine kinase mRNA), growth curve analysis |
Molecular and cellular biology |
Medium |
3600660
|
| 2016 |
SPRED1 specifically perturbs K-ras (but not H-ras) membrane organization and ERK signaling at the plasma membrane by becoming enriched in acidic membrane domains. However, SPRED1 does block the positive effects of galectin-1 on H-ras nanoclustering. Legius syndrome-associated SPRED1 mutations show diminished binding to both galectin-1 and B-Raf. |
SPRED1 overexpression and membrane domain analysis, H-ras vs. K-ras ERK signaling assays, galectin-1 co-expression, Legius syndrome mutant analysis, plasma membrane fractionation |
Molecular and cellular biology |
Medium |
27503857
|
| 2004 |
H-Ras and K-Ras exert distinct effects on apoptosis in endometrial cells: activated H-Ras rescues cells from apoptosis (dependent on PI3K/Akt), whereas activated K-Ras promotes apoptosis (dependent on Raf/MEK/MAPK). These isoform-specific differences depend on effector domain interactions, as demonstrated by K-Ras effector domain mutants (K12V35S preferentially activating MAPK/apoptosis; K12V40C preferentially activating Akt/survival). |
Stable expression of activated H-Ras and K-Ras, MEK inhibitor (U0126) and PI3K inhibitor (LY294002) epistasis, K-Ras effector domain mutants (35S and 40C), apoptosis assays, MAPK/Akt phosphorylation |
Cancer research |
Medium |
15087391
|