{"gene":"SHOC2","run_date":"2026-06-10T07:46:31","timeline":{"discoveries":[{"year":1998,"finding":"C. elegans SUR-8 (SHOC2 ortholog) acts downstream of or in parallel to RAS but upstream of RAF in the RAS-MAPK pathway, as established by genetic epistasis: sur-8 loss suppresses activated ras and enhances mpk-1/ksr-1 phenotypes. The human SUR-8 homolog directly binds K-Ras and N-Ras but not H-Ras in vitro.","method":"Genetic epistasis (suppressor/enhancer screens in C. elegans), direct protein binding assay (in vitro pull-down with RAS isoforms)","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — genetic epistasis in C. elegans plus in vitro binding assay; foundational mechanism paper, replicated by subsequent work","pmids":["9674433"],"is_preprint":false},{"year":1998,"finding":"SOC-2/SHOC2 encodes a leucine-rich repeat protein functioning downstream of the EGL-15 FGF receptor in C. elegans. Human SHOC-2 protein is cytoplasmically localized. SHOC2 is not observed to be tyrosine phosphorylated in response to FGF stimulation, and phosphorylation of YXNX motifs is not required for SOC-2 function in vivo.","method":"Genetic suppressor screen, subcellular localization by immunofluorescence, phosphorylation assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — genetic epistasis plus direct localization experiment, but some findings are negative results; single lab","pmids":["9618511"],"is_preprint":false},{"year":2000,"finding":"Human Sur-8 (SHOC2) forms a ternary complex with Ras and Raf, interacting with both proteins simultaneously. Sur-8 enhances Ras- or EGF-induced Raf and ERK activation but has no effect on ERK activation by active Raf or MEK, and does not increase AKT or JNK activation, placing its action between Ras and Raf.","method":"Co-immunoprecipitation, pulldown, overexpression assays with epistasis (active Raf/MEK bypass), kinase activation assays","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP establishing ternary complex, epistasis placing SHOC2 between RAS and RAF, replicated across multiple subsequent studies","pmids":["10783161"],"is_preprint":false},{"year":2005,"finding":"Erbin inhibits ERK activation by disrupting the Sur-8–Ras–Raf complex: Erbin's LRR domain interacts with Sur-8 and reduces Sur-8 binding to active Ras and Raf. Erbin knockdown increases Sur-8–Ras/Raf interaction and ERK activation.","method":"Co-immunoprecipitation, Erbin shRNA knockdown, reporter assays, interaction mapping","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — reciprocal Co-IP plus shRNA loss-of-function with defined molecular phenotype; single lab","pmids":["16301319"],"is_preprint":false},{"year":2006,"finding":"SHOC2 (Sur-8) and the catalytic subunit of protein phosphatase 1 (PP1c) form a complex that acts as a highly specific M-Ras effector. This SHOC2-PP1c holoenzyme dephosphorylates the inhibitory S259 site on RAF (bound to M-Ras or Ras), thereby activating RAF and the MAPK pathway. SHOC2 function is essential for MAPK (but not PI3K) pathway activation by growth factors in tumor cells.","method":"Proteomics (mass spectrometry), Co-immunoprecipitation, in vitro phosphatase assay, RNAi knockdown with pathway readouts","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — proteomics identification plus in vitro phosphatase assay plus RNAi epistasis; foundational mechanistic discovery, independently replicated","pmids":["16630891"],"is_preprint":false},{"year":2009,"finding":"The disease-causing S2G mutation in SHOC2 introduces an N-myristoylation site (requires N-terminal glycine), causing aberrant constitutive targeting of SHOC2 to the plasma membrane and impaired translocation to the nucleus upon growth factor stimulation. This mislocalization results in cell-type-specific enhancement of MAPK activation.","method":"N-myristoylation assay, subcellular fractionation/live imaging, mutant expression in mammalian cells and C. elegans, MAPK activation assays","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct biochemical demonstration of N-myristoylation, subcellular localization experiment with functional consequence, in vivo C. elegans validation; multiple orthogonal methods","pmids":["19684605"],"is_preprint":false},{"year":2010,"finding":"SHOC2 (Shoc2/SUR-8) acts as a scaffold that accelerates both the association and dissociation of Ras–Raf interaction (accelerator model), as demonstrated by FRET biosensor live-cell imaging and computational modeling. SHOC2 knockdown reduces MEK/ERK phosphorylation but not Ras activation.","method":"FRET biosensor (live-cell imaging), RNAi knockdown, computational modeling","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — direct live-cell FRET measurement of Ras-Raf interaction kinetics, supported by computational modeling; mechanistically precise, single lab but two complementary orthogonal methods","pmids":["20051520"],"is_preprint":false},{"year":2010,"finding":"Shoc2 scaffold protein is required for Ca²⁺/calmodulin-dependent activation of Raf1 at the plasma membrane downstream of Ras. Ca²⁺-dependent Raf1 activation was abolished by Shoc2 knockdown, demonstrating Shoc2 integrates Ras and Ca²⁺ signaling inputs at Raf1.","method":"FRET biosensor, RNAi knockdown, pharmacological manipulation of Ca²⁺/calmodulin, synthetic GEF (eGRF) system","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — FRET-based live imaging plus shRNA epistasis; single lab, two orthogonal methods","pmids":["20071468"],"is_preprint":false},{"year":2010,"finding":"Endothelial-specific deletion of SUR-8 in mice causes late embryonic lethality with cardiac defects including hypoplastic endocardial cushions due to reduced endothelial-mesenchymal transformation, but ERK activation is not affected in mutant endothelial cells, indicating SUR-8 acts in an ERK-independent pathway during atrioventricular cushion development.","method":"Conditional (endothelial-specific) knockout mouse, histological analysis, ERK activation assays","journal":"Developmental dynamics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean conditional KO with defined cellular phenotype and negative ERK activation result; single lab","pmids":["20549726"],"is_preprint":false},{"year":2012,"finding":"Shoc2 localizes to late endosomes (Rab7-positive) upon EGFR activation in a RAS-activity- and clathrin-dependent manner. Endosomal targeting is required for ERK1/2 activation at physiological EGF concentrations. The disease-causing S2G myristoylated mutant is excluded from late endosomes (found on plasma membrane and early endosomes) and fails to rescue ERK1/2 activation in Shoc2-depleted cells.","method":"Live-cell imaging (RFP-tagged Shoc2), RNAi (clathrin, H-RAS dominant-negative), rescue experiments, subcellular fractionation","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct localization experiment with functional consequence (ERK rescue), dominant-negative and RNAi epistasis, multiple orthogonal methods; single lab","pmids":["22606262"],"is_preprint":false},{"year":2012,"finding":"SHOC2 (Sur-8) and CRAF mediate ERK1/2 reactivation in BRAF(V600E)/NRAS(Q61K) cells during RAF inhibitor treatment. ERK1/2 activation and resistance to apoptosis in these cells require the RAF-binding site of NRAS and are modulated by SHOC-2 expression.","method":"siRNA knockdown, kinase activation assays, apoptosis assays, mutant expression","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — siRNA knockdown with defined pathway and apoptosis phenotype; single lab, two orthogonal readouts","pmids":["23076151"],"is_preprint":false},{"year":2013,"finding":"SHOC2 forms a macromolecular complex with MRAS and SCRIB. SCRIB functions as a PP1-regulatory protein and antagonizes SHOC2-mediated RAF dephosphorylation through competition for PP1 molecules within the same complex. SHOC2 function is selectively required for malignant properties of RAS-mutant tumor cells; MRAS and SHOC2 play a key role in polarized migration.","method":"Co-immunoprecipitation, mass spectrometry, shRNA knockdown, RAF dephosphorylation assay, migration assays","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Moderate — MS-identified complex, Co-IP, in vitro phosphatase competition assay, loss-of-function phenotype; single lab but multiple orthogonal methods","pmids":["24211266"],"is_preprint":false},{"year":2013,"finding":"SHOC2 has two main structural domains: an N-terminal non-LRR domain mediating binding to both M-Ras and Raf-1, and a C-terminal LRR region containing a late endosomal targeting motif. M-Ras binding to Shoc2 is independent of M-Ras GTPase activity.","method":"Domain deletion/mutation analysis, Co-immunoprecipitation, rescue experiments in Shoc2-depleted cells","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — systematic domain-mapping by Co-IP and rescue; single lab, multiple domain constructs tested","pmids":["23805200"],"is_preprint":false},{"year":2014,"finding":"A novel SHOC2 mutation (M173I) causes a Rasopathy by impairing SHOC2 binding to PP1c, leading to insufficient RAF-1 kinase activation and failure to fully rescue ERK1/2 activity in SHOC2-depleted cells.","method":"Co-immunoprecipitation, rescue assay in SHOC2-depleted cells, ERK1/2 phosphorylation assay","journal":"Human mutation","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — Co-IP and functional rescue assay with clear mechanistic consequence; single lab","pmids":["25137548"],"is_preprint":false},{"year":2014,"finding":"HUWE1 E3 ubiquitin ligase is a binding partner and regulator of Shoc2: HUWE1 mediates ubiquitination of Shoc2 (controlling Shoc2 levels) and also controls ubiquitination and levels of RAF-1 within the Shoc2 complex. HUWE1-mediated Shoc2 ubiquitination acts as a switch regulating RAF-1 kinase activity transition from active to inactive state.","method":"Co-immunoprecipitation, ubiquitination assays, siRNA knockdown, ERK1/2 pathway activation assays","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — Co-IP, ubiquitination assay, and knockdown with pathway readout; single lab, multiple orthogonal methods","pmids":["25022756"],"is_preprint":false},{"year":2015,"finding":"The AAA+ ATPase PSMC5 is a binding partner of Shoc2 that triggers Shoc2 translocation to endosomes. At endosomes, PSMC5 displaces HUWE1 from the Shoc2 scaffold complex, attenuating ubiquitylation of both Shoc2 and RAF-1. The Noonan-like S2G mutation alters Shoc2 subcellular distribution, reducing PSMC5 accessibility and thereby altering Shoc2 ubiquitylation.","method":"Co-immunoprecipitation, subcellular fractionation/live imaging, ubiquitylation assays, knockdown experiments","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — Co-IP plus localization experiment with functional ubiquitylation consequence; single lab, multiple orthogonal methods","pmids":["26519477"],"is_preprint":false},{"year":2015,"finding":"Sur8/Shoc2 interacts with the p110α subunit of PI3K (in addition to Ras and Raf), with interactions increased in an EGF- and oncogenic Ras-dependent manner. Sur8 regulates cell migration and invasion via PI3K-dependent Rac activation and MMP upregulation.","method":"Co-immunoprecipitation, kinase inhibitor experiments, migration/invasion assays, lentiviral knockdown","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP establishing new binding partner, pharmacological epistasis, loss-of-function with migration phenotype; single lab","pmids":["26384305"],"is_preprint":false},{"year":2016,"finding":"SHOC2 nuclear-cytoplasmic shuttling requires LRRs 1–13 for nuclear import and constitutive plasma membrane targeting of S2G, while the KEKE motif-rich N-terminal region is necessary for efficient nuclear export. SHOC2 trapping at different subcellular compartments has distinct impacts on ERK signaling strength and dynamics, suggesting a dual modulatory role at different intracellular sites.","method":"Domain deletion/mutation constructs, live-cell imaging, subcellular fractionation, ERK activation assays","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — systematic domain mapping with localization and functional ERK readouts; single lab, multiple orthogonal methods","pmids":["27466182"],"is_preprint":false},{"year":2017,"finding":"PKCα and PKCδ phosphorylate Sur8 at Thr-71 and Ser-297, respectively, promoting polyubiquitin-dependent degradation of Sur8. FGF2 stabilizes Sur8 by reducing this PKC-mediated phosphorylation and degradation.","method":"Phosphorylation mutagenesis, ubiquitination assays, kinase activity assays, co-immunoprecipitation","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — site-specific mutagenesis and ubiquitination assay identifying specific phosphorylation sites; single lab","pmids":["29383184"],"is_preprint":false},{"year":2018,"finding":"The MRAS-SHOC2-PP1 heterotrimeric holoenzyme dephosphorylates the inhibitory S259 site on RAF kinases; MRAS and SHOC2 function as PP1 regulatory subunits conferring striking substrate specificity toward RAF. Membrane localization of MRAS is required for efficient RAF dephosphorylation in cells. SHOC2's predicted structure resembles the A subunit of PP2A. Multiple SHOC2 regions and MRAS switch I/interswitch residues mediate complex formation. Noonan syndrome mutations in SHOC2, MRAS, and PPP1CB invariably promote ternary complex formation.","method":"In vitro phosphatase assay, Co-immunoprecipitation, membrane targeting experiments, mutagenesis, structural prediction","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro phosphatase reconstitution, mutagenesis, multiple orthogonal methods; replicated by subsequent structural papers","pmids":["30348783"],"is_preprint":false},{"year":2019,"finding":"SHOC2 complex (SHOC2-MRAS-PP1)-mediated S259 RAF dephosphorylation is critically required for growth factor-induced RAF heterodimerization and MEK dissociation from BRAF. SHOC2 is essential for a rapid transient phase of ERK activation induced by EGF, while a slow sustained phase driven by palmitoylated H/N-RAS and CRAF is SHOC2-independent. KRAS mutant cells preferentially rely on SHOC2 for ERK signaling under anchorage-independent conditions.","method":"SHOC2 knockout/knockdown, RAF dimerization assays, MEK co-immunoprecipitation, ERK activation time-course, anchorage-independent growth assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — KO with multiple defined molecular phenotypes (RAF dimerization, MEK dissociation, ERK kinetics) using multiple orthogonal methods; context-dependent epistasis established","pmids":["31213532"],"is_preprint":false},{"year":2019,"finding":"SHOC2 deletion prevents MEKi-induced RAF dimerization, leading to more potent and durable ERK pathway suppression and BIM-dependent apoptosis. Systemic SHOC2 ablation in adult mice is relatively well tolerated. SHOC2 deletion selectively sensitizes KRAS- and EGFR-mutant NSCLC cells to MEK inhibitors.","method":"Genetic SHOC2 knockout (CRISPR), murine autochthonous cancer models, RAF dimerization assays, apoptosis assays (BIM), combination drug treatment","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Moderate — CRISPR KO with defined RAF dimerization mechanism, in vivo mouse model, apoptosis mechanistic readout; single lab with multiple orthogonal methods","pmids":["31182717"],"is_preprint":false},{"year":2019,"finding":"SHOC2 is a substrate of the FBXW7 E3 ubiquitin ligase. Growth stimuli trigger SHOC2 phosphorylation on Thr507 by the MAPK signal, which facilitates FBXW7 binding for ubiquitylation and degradation, establishing a negative feedback loop. Additionally, SHOC2 selectively binds Raptor (mTORC1 component) to competitively inhibit Raptor-mTOR binding, inactivating mTORC1 and inducing autophagy; Raptor binding to SHOC2 inhibits SHOC2-RAS binding to block MAPK signaling.","method":"Co-immunoprecipitation, ubiquitination assays, phosphorylation site mapping/mutagenesis (Thr507), mTORC1 activity assays, competitive binding assays","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — Co-IP, ubiquitination assay, phospho-site mutagenesis, and competition assay; single lab, multiple orthogonal methods","pmids":["30865892"],"is_preprint":false},{"year":2019,"finding":"M-Ras/Shoc2 signaling contributes to E-cadherin/p120-catenin junction turnover required for collective cell migration. Activated M-Ras recruits Shoc2 to cell surface junctions. Loss of Shoc2 reduces junction turnover and impairs collective migration. The regulatory effect requires downstream ERK cascade activation and involves phosphoregulation of p120-catenin. The myristoylated Shoc2 S2G Noonan mutant causes gain-of-function increased junction turnover and less cohesive migration.","method":"Dominant-negative M-Ras expression, SHOC2 knockdown/reconstitution, E-cadherin/p120-catenin co-immunoprecipitation, live-cell imaging of junction dynamics, zebrafish embryo gastrulation assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Moderate — depletion/reconstitution with multiple orthogonal methods (Co-IP, live imaging, in vivo zebrafish), mechanistic pathway placement via ERK epistasis; single lab","pmids":["30808747"],"is_preprint":false},{"year":2019,"finding":"VCP/p97 ATPase activity controls stoichiometry of HUWE1 in the Shoc2 complex and modulates HUWE1-mediated allosteric ubiquitination of Shoc2 and RAF-1. Abrogated VCP ATPase activity augments Shoc2/RAF-1 ubiquitination and alters RAF-1 phosphorylation and ERK1/2 signaling. Fibroblasts from IBMPFD patients with germline VCP mutations show imbalanced Shoc2 ubiquitination and ERK1/2 phosphorylation.","method":"Co-immunoprecipitation, ubiquitination assays, VCP ATPase mutant expression, patient-derived fibroblasts","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — Co-IP and ubiquitination assay with ATPase mutant and patient cells; single lab, two orthogonal approaches","pmids":["31091164"],"is_preprint":false},{"year":2021,"finding":"USP7, a ubiquitin-specific protease, interacts with Shoc2 in an ERK1/2-activation-dependent manner. Within the Shoc2 module, USP7 functions as a molecular 'switch' controlling HUWE1 E3 ligase activity and the HUWE1-induced regulatory feedback loop. Disruption of Shoc2-USP7 binding leads to aberrant ERK1/2 axis activation.","method":"Co-immunoprecipitation, USP7 knockdown/inhibition, ERK1/2 activation assays, HUWE1 activity assays","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — Co-IP with pathway-dependent timing, loss-of-function with defined molecular phenotype; single lab","pmids":["34553755"],"is_preprint":false},{"year":2022,"finding":"Cryo-EM structures of the SHOC2-MRAS-PP1C complex (two independent studies, ~3 Å resolution) reveal a tripartite architecture: crescent-shaped SHOC2 acts as a cradle bridging PP1C and MRAS through its concave LRR surface. SHOC2 also engages PP1C through an N-terminal disordered region containing a cryptic RVXF motif. Complex assembly is initiated by SHOC2-PP1C interaction and stabilized by GTP-loaded MRAS. RASopathy mutations reside at protein-protein interfaces and enhance holoenzyme affinity. Deep mutational scanning comprehensively maps functional residues of SHOC2. Multiple RAS isoforms can substitute for MRAS in a GTP-dependent manner.","method":"Cryo-electron microscopy, X-ray crystallography, deep mutational scanning, biophysical binding assays, mutagenesis","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — atomic-resolution cryo-EM structure plus deep mutational scanning plus biophysical validation; replicated by three independent structural studies in the same year","pmids":["35831509","35768504","35830882","36175670"],"is_preprint":false},{"year":2022,"finding":"Crystal structure of the SHOC2-MRAS-PP1C complex shows all three proteins synergistically interact with each other. PP1C substrate specificity toward RAF is enhanced upon interaction with both SHOC2 and MRAS. Complex forms only when MRAS is GTP-bound. SHOC2 functions as scaffolding protein bringing PP1C and MRAS together. Noonan syndrome mutations enhance complex formation.","method":"X-ray crystallography, in vitro phosphatase assay with RAF substrates, biophysical binding assays, mutagenesis","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus in vitro reconstituted phosphatase activity assay with mutagenesis; independent replication of related structures","pmids":["36175670"],"is_preprint":false},{"year":2024,"finding":"NRAS(Q61R) forms a direct protein-protein interaction with SHOC2, revealed by X-ray co-crystal structure. SHOC2 is a dependency of RAS(Q61*) tumors in a nucleotide-state-dependent manner. Small molecules disrupting the SHOC2–RAS(Q61*) interaction inhibit MAPK signaling and proliferation in RAS-mutant cancer models.","method":"X-ray co-crystallography, CRISPR dependency screens, in vitro high-throughput small-molecule screening, MAPK signaling assays, proliferation assays","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — X-ray co-crystal structure establishing direct interaction, corroborated by pharmacological disruption and genetic dependency; multiple orthogonal methods","pmids":["40335703"],"is_preprint":false},{"year":2024,"finding":"In cells expressing NSLH-associated Shoc2 variants, when both AKT and ERK1/2 pathways are activated downstream of EGFR, AKT signaling triggers PAK activation followed by Raf-1/MEK1/2 phosphorylation and ERK1/2 activation, revealing a previously unrecognized AKT-PAK-RAF feedback crosstalk. In contrast, when ERK1/2 is the primary EGFR effector, Shoc2 variants cannot upregulate ERK1/2 to wild-type levels.","method":"Mutant expression/reconstitution, pathway inhibitor epistasis, ERK1/2 and AKT phosphorylation assays","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — mutant reconstitution plus pharmacological epistasis identifying novel feedback; single lab, two orthogonal methods","pmids":["38881369"],"is_preprint":false},{"year":2025,"finding":"Loss of Shoc2 in zebrafish and lymphatic endothelial cells results in near-complete loss of lymphatic vasculature and cellular senescence. Mechanistically, Shoc2 loss increases mTORC1 signaling, impairs mitochondrial respiration, and triggers an IRF/IFN-II innate immune response leading to senescence. The NSLH-causing S2G variant phenocopies Shoc2 loss in this context.","method":"Zebrafish genetic loss-of-function, in vitro lymphatic endothelial cell assays, mTORC1 activity assays, mitochondrial respiration assay, IFN pathway assays","journal":"Cell death and differentiation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo and in vitro loss-of-function with multiple mechanistic readouts; single lab, multiple orthogonal methods","pmids":["41946973"],"is_preprint":false}],"current_model":"SHOC2 is a leucine-rich repeat scaffold protein that forms a heterotrimeric holophosphatase complex with M-RAS (GTP-bound) and PP1C; within this complex—whose atomic structure has been determined by cryo-EM and X-ray crystallography—SHOC2 bridges PP1C and M-RAS through its concave LRR surface and an N-terminal RVXF motif to dephosphorylate the inhibitory S259 site on RAF kinases, thereby promoting RAF heterodimerization, MEK/ERK pathway activation, and normal development; its scaffold function is spatiotemporally regulated by PSMC5-dependent endosomal translocation, HUWE1- and FBXW7-mediated ubiquitination/degradation, USP7-controlled deubiquitination, and PKC-mediated phospho-degron formation, while the disease-associated S2G mutation aberrantly N-myristoylates SHOC2 to the plasma membrane, preventing endosomal targeting and dysregulating ERK signaling dynamics."},"narrative":{"mechanistic_narrative":"SHOC2 is a leucine-rich repeat scaffold protein that positions RAS-family GTPases for activation of the RAF–MEK–ERK cascade, acting genetically downstream of RAS but upstream of RAF [PMID:9674433, PMID:10783161]. Its central biochemical function is as the scaffolding subunit of a heterotrimeric holophosphatase formed with GTP-loaded M-RAS and the catalytic subunit of protein phosphatase 1 (PP1C); within this complex SHOC2 confers RAF substrate specificity, and the holoenzyme dephosphorylates the inhibitory S259 site on RAF kinases to relieve autoinhibition [PMID:16630891, PMID:30348783]. Cryo-EM and crystal structures show that crescent-shaped SHOC2 cradles PP1C and M-RAS through its concave LRR surface and an N-terminal disordered RVXF motif, with assembly initiated by SHOC2–PP1C binding and stabilized only when M-RAS (or substituting RAS isoforms) is GTP-bound [PMID:35831509, PMID:35768504, PMID:35830882, PMID:36175670]. This S259 dephosphorylation licenses growth factor-induced RAF heterodimerization and MEK release from BRAF, and SHOC2 is selectively required for the rapid transient phase of ERK activation and for ERK signaling in RAS-mutant cells under anchorage-independent conditions [PMID:30348783, PMID:31213532]. SHOC2 scaffold activity is spatiotemporally controlled: EGFR/RAS-driven, clathrin-dependent translocation to Rab7 late endosomes is required for ERK activation, and a ubiquitination cycle involving HUWE1, FBXW7, the PSMC5 ATPase, and USP7 tunes SHOC2 and RAF-1 levels and signaling output [PMID:22606262, PMID:25022756, PMID:26519477, PMID:30865892, PMID:34553755]. Loss of SHOC2 prevents MEK-inhibitor-induced RAF dimerization and selectively sensitizes KRAS- and EGFR-mutant tumors to MEK inhibition, while direct SHOC2–RAS(Q61) interaction makes it a druggable dependency in RAS(Q61)-mutant cancers [PMID:31182717, PMID:40335703]. Gain-of-function in this scaffold underlies Noonan-like RASopathy: the S2G mutation introduces an N-myristoylation site that mistargets SHOC2 to the plasma membrane and excludes it from late endosomes, dysregulating ERK dynamics, and RASopathy mutations in SHOC2, MRAS, and PPP1CB invariably enhance ternary complex formation [PMID:19684605, PMID:22606262, PMID:30348783].","teleology":[{"year":1998,"claim":"Established where SHOC2 acts in the RAS-MAPK pathway, placing it downstream of RAS and upstream of RAF rather than as a generic adaptor.","evidence":"Genetic epistasis in C. elegans plus in vitro RAS-isoform binding assays for the human ortholog","pmids":["9674433","9618511"],"confidence":"High","gaps":["Did not define the biochemical activity of the complex","Mechanism of how SUR-8 couples RAS to RAF unresolved","Isoform selectivity (K/N-RAS vs H-RAS) not mechanistically explained"]},{"year":2000,"claim":"Showed SHOC2 forms a ternary complex bridging RAS and RAF simultaneously and enhances RAS/EGF-induced RAF–ERK activation, supporting a scaffold model acting between RAS and RAF.","evidence":"Reciprocal Co-IP and kinase activation assays with active RAF/MEK bypass","pmids":["10783161"],"confidence":"High","gaps":["No enzymatic activity attributed to the complex","Did not identify additional subunits"]},{"year":2006,"claim":"Defined the molecular function of the complex: SHOC2–PP1C is an M-RAS effector holophosphatase that dephosphorylates the inhibitory S259 RAF site to activate MAPK.","evidence":"Mass spectrometry, in vitro phosphatase assay, and RNAi with pathway readouts","pmids":["16630891"],"confidence":"High","gaps":["Structural basis of substrate specificity unknown","How PP1C is targeted specifically to RAF unresolved at the time"]},{"year":2009,"claim":"Connected SHOC2 to RASopathy disease by showing the S2G mutation creates an N-myristoylation site causing aberrant plasma membrane targeting and dysregulated MAPK activation.","evidence":"N-myristoylation assay, subcellular localization, mutant expression in cells and C. elegans","pmids":["19684605"],"confidence":"High","gaps":["Did not establish the normal localization signal mislocalized by S2G","Cell-type specificity of MAPK enhancement not mechanistically explained"]},{"year":2010,"claim":"Provided kinetic and signaling-integration detail: SHOC2 accelerates RAS–RAF association/dissociation and integrates Ca2+/calmodulin inputs at RAF1.","evidence":"Live-cell FRET biosensors, computational modeling, RNAi, and pharmacological Ca2+ manipulation","pmids":["20051520","20071468"],"confidence":"High","gaps":["Single lab for the accelerator model","Relationship between scaffold kinetics and the holophosphatase activity not reconciled"]},{"year":2012,"claim":"Showed that SHOC2 endosomal trafficking is functionally required, localizing to Rab7 late endosomes in a RAS- and clathrin-dependent manner to drive ERK activation, which the S2G mutant fails to do.","evidence":"Live-cell imaging, RNAi/dominant-negative epistasis, and rescue experiments","pmids":["22606262"],"confidence":"High","gaps":["Identity of endosomal targeting machinery not fully defined","Whether holophosphatase activity occurs at endosomes unresolved"]},{"year":2013,"claim":"Identified SCRIB as a competing PP1-regulatory antagonist within the SHOC2 complex and mapped SHOC2 domains, establishing competitive regulation of RAF dephosphorylation.","evidence":"MS, Co-IP, in vitro phosphatase competition, and domain deletion analysis","pmids":["24211266","23805200"],"confidence":"High","gaps":["Domain assignments later refined by structural work","Physiological contexts where SCRIB competition dominates not defined"]},{"year":2014,"claim":"Established ubiquitin-mediated control of the scaffold: HUWE1 ubiquitinates SHOC2 and RAF-1 as a switch for RAF activity, and a RASopathy M173I mutation impairing PP1C binding causes insufficient RAF activation.","evidence":"Co-IP, ubiquitination assays, siRNA, and rescue/ERK assays","pmids":["25022756","25137548"],"confidence":"Medium","gaps":["Single-lab HUWE1 findings","Spatial coordination of ubiquitination with endosomal targeting unclear"]},{"year":2015,"claim":"Connected trafficking and turnover by showing PSMC5 drives SHOC2 endosomal translocation and displaces HUWE1 to attenuate ubiquitylation, with S2G disrupting this regulation.","evidence":"Co-IP, live imaging, and ubiquitylation assays with knockdowns","pmids":["26519477"],"confidence":"Medium","gaps":["Single lab","Mechanism of PSMC5-mediated HUWE1 displacement not structurally defined"]},{"year":2018,"claim":"Identified PKC-dependent phospho-degron formation (Thr-71, Ser-297) promoting SHOC2 degradation, with FGF2 stabilizing SHOC2 by reducing this phosphorylation.","evidence":"Site-specific mutagenesis, ubiquitination and kinase assays, Co-IP","pmids":["29383184"],"confidence":"Medium","gaps":["E3 ligase coupling these sites to degradation not defined here","Single lab"]},{"year":2019,"claim":"Resolved the downstream signaling consequence and therapeutic relevance: SHOC2-mediated S259 dephosphorylation licenses RAF heterodimerization and MEK release, governs transient ERK kinetics, and its loss sensitizes KRAS/EGFR-mutant tumors to MEK inhibition.","evidence":"SHOC2 KO/knockdown, RAF dimerization and MEK Co-IP assays, ERK time-courses, murine cancer models, and apoptosis assays","pmids":["31213532","31182717"],"confidence":"High","gaps":["Structural basis of RAF specificity not yet resolved","Context-dependence across RAS isoforms incompletely mapped"]},{"year":2019,"claim":"Expanded SHOC2 regulation and outputs beyond MAPK: FBXW7-mediated negative feedback via Thr507 phosphorylation, mTORC1 inhibition via Raptor competition, junction-turnover control of collective migration, and VCP/p97 tuning of HUWE1 stoichiometry.","evidence":"Co-IP, ubiquitination/phospho-site mutagenesis, competition and mTORC1 assays, junction live imaging, zebrafish, and patient fibroblasts","pmids":["30865892","30808747","31091164"],"confidence":"Medium","gaps":["mTORC1/Raptor and MAPK roles not integrated mechanistically","Several findings single-lab","Physiological weighting of these alternate functions unclear"]},{"year":2021,"claim":"Identified USP7 as a deubiquitinase switch acting in an ERK-activation-dependent manner to control HUWE1 activity within the SHOC2 module.","evidence":"Co-IP, USP7 knockdown/inhibition, and ERK/HUWE1 activity assays","pmids":["34553755"],"confidence":"Medium","gaps":["Single lab","How USP7 timing couples to endosomal/PSMC5 events unclear"]},{"year":2022,"claim":"Provided atomic-resolution architecture of the SHOC2–MRAS–PP1C holoenzyme, showing SHOC2 cradles PP1C and MRAS via its concave LRR surface and an N-terminal RVXF motif, with GTP-MRAS-dependent assembly and RASopathy mutations enhancing affinity.","evidence":"Cryo-EM, X-ray crystallography, deep mutational scanning, and biophysical/phosphatase assays across independent studies","pmids":["35831509","35768504","35830882","36175670"],"confidence":"High","gaps":["Structural state of RAF substrate engagement not captured","Endosomal/regulatory context not in the structures"]},{"year":2024,"claim":"Demonstrated a direct druggable SHOC2–RAS(Q61) interface and a novel AKT-PAK-RAF feedback route used by RASopathy variants, advancing both therapeutic targeting and disease mechanism.","evidence":"X-ray co-crystallography, CRISPR dependency screens, small-molecule screening, and pathway-inhibitor epistasis","pmids":["40335703","38881369"],"confidence":"High","gaps":["Generality of the AKT-PAK-RAF crosstalk beyond variant cells unclear","In vivo efficacy/selectivity of SHOC2–RAS disruptors not established here"]},{"year":2025,"claim":"Linked SHOC2 to lymphatic development and cellular homeostasis via mTORC1, mitochondrial respiration, and an IRF/IFN-II senescence program, with S2G phenocopying loss.","evidence":"Zebrafish and lymphatic endothelial cell loss-of-function with mTORC1, respiration, and IFN pathway assays","pmids":["41946973"],"confidence":"Medium","gaps":["Single lab","Connection between MAPK/holophosphatase function and the senescence phenotype not mechanistically bridged"]},{"year":null,"claim":"How SHOC2's distinct activities — endosomal scaffolding, the ternary holophosphatase, ubiquitin/phospho regulatory cycles, and mTORC1/migration/senescence outputs — are spatiotemporally coordinated within a single cell remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model integrating trafficking, holophosphatase assembly, and turnover","Relative contribution of MAPK-independent functions to development unquantified","Structural capture of the SHOC2 complex engaging RAF substrate is lacking"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,4,26,27]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,11,19]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[4,19,27]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,2,28]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[9,15]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[5,7,23]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[5,17]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2,4,19,20]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[5,13,19,28]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[8,23,30]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[22]}],"complexes":["SHOC2-MRAS-PP1C holophosphatase"],"partners":["MRAS","PPP1CB","RAF1","SCRIB","HUWE1","FBXW7","USP7","PSMC5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9UQ13","full_name":"Leucine-rich repeat protein SHOC-2","aliases":["Protein soc-2 homolog","Protein sur-8 homolog"],"length_aa":582,"mass_kda":64.9,"function":"Core component of the SHOC2-MRAS-PP1c (SMP) holophosphatase complex that regulates activation of the MAPK pathway (PubMed:10783161, PubMed:16630891, PubMed:25137548, PubMed:35768504, PubMed:35830882, PubMed:35831509, PubMed:36175670). Acts as a scaffolding protein in the SMP complex (PubMed:35768504, PubMed:35830882, PubMed:35831509, PubMed:36175670). The SMP complex specifically dephosphorylates the inhibitory phosphorylation at 'Ser-259' of RAF1 kinase, 'Ser-365' of BRAF kinase and 'Ser-214' of ARAF kinase, stimulating their kinase activities (PubMed:10783161, PubMed:16630891, PubMed:35768504, PubMed:35830882, PubMed:35831509, PubMed:36175670). The SMP complex enhances the dephosphorylation activity and substrate specificity of PP1c (PubMed:35768504, PubMed:36175670)","subcellular_location":"Cytoplasm; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9UQ13/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SHOC2","classification":"Not Classified","n_dependent_lines":238,"n_total_lines":1208,"dependency_fraction":0.19701986754966888},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/SHOC2","total_profiled":1310},"omim":[{"mim_id":"608435","title":"MUSCLE RAS VIRAL ONCOGENE HOMOLOG; MRAS","url":"https://www.omim.org/entry/608435"},{"mim_id":"607721","title":"NOONAN SYNDROME-LIKE DISORDER WITH LOOSE ANAGEN HAIR 1; NSLH1","url":"https://www.omim.org/entry/607721"},{"mim_id":"602775","title":"SHOC2 LEUCINE-RICH REPEAT SCAFFOLD PROTEIN; SHOC2","url":"https://www.omim.org/entry/602775"},{"mim_id":"600590","title":"PROTEIN PHOSPHATASE 1, CATALYTIC SUBUNIT, BETA ISOFORM; PPP1CB","url":"https://www.omim.org/entry/600590"},{"mim_id":"600574","title":"LEUCINE ZIPPER-LIKE TRANSCRIPTIONAL REGULATOR 1; LZTR1","url":"https://www.omim.org/entry/600574"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SHOC2"},"hgnc":{"alias_symbol":["KIAA0862","SOC2","SUR-8","SOC-2","SUR8"],"prev_symbol":[]},"alphafold":{"accession":"Q9UQ13","domains":[{"cath_id":"3.80.10.10","chopping":"89-202","consensus_level":"medium","plddt":96.9057,"start":89,"end":202},{"cath_id":"3.80.10.10","chopping":"205-309","consensus_level":"medium","plddt":97.683,"start":205,"end":309}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UQ13","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UQ13-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UQ13-F1-predicted_aligned_error_v6.png","plddt_mean":87.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SHOC2","jax_strain_url":"https://www.jax.org/strain/search?query=SHOC2"},"sequence":{"accession":"Q9UQ13","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UQ13.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UQ13/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UQ13"}},"corpus_meta":[{"pmid":"19684605","id":"PMC_19684605","title":"Mutation of SHOC2 promotes aberrant protein N-myristoylation and causes Noonan-like syndrome with loose anagen hair.","date":"2009","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19684605","citation_count":313,"is_preprint":false},{"pmid":"16630891","id":"PMC_16630891","title":"A phosphatase holoenzyme comprised of Shoc2/Sur8 and the catalytic subunit of PP1 functions as an M-Ras effector to modulate Raf activity.","date":"2006","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/16630891","citation_count":178,"is_preprint":false},{"pmid":"9674433","id":"PMC_9674433","title":"SUR-8, a conserved Ras-binding protein with leucine-rich repeats, positively regulates Ras-mediated signaling in C. elegans.","date":"1998","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/9674433","citation_count":175,"is_preprint":false},{"pmid":"10783161","id":"PMC_10783161","title":"The leucine-rich repeat protein SUR-8 enhances MAP kinase activation and forms a complex with Ras and Raf.","date":"2000","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/10783161","citation_count":116,"is_preprint":false},{"pmid":"9618511","id":"PMC_9618511","title":"soc-2 encodes a leucine-rich repeat protein implicated in fibroblast growth factor receptor signaling.","date":"1998","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/9618511","citation_count":99,"is_preprint":false},{"pmid":"24211266","id":"PMC_24211266","title":"An MRAS, SHOC2, and SCRIB complex coordinates ERK pathway activation with polarity and tumorigenic growth.","date":"2013","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/24211266","citation_count":96,"is_preprint":false},{"pmid":"16301319","id":"PMC_16301319","title":"Erbin inhibits RAF activation by disrupting the sur-8-Ras-Raf complex.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16301319","citation_count":88,"is_preprint":false},{"pmid":"31577942","id":"PMC_31577942","title":"Synthetic Lethal Interaction of SHOC2 Depletion with MEK Inhibition in RAS-Driven Cancers.","date":"2019","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/31577942","citation_count":78,"is_preprint":false},{"pmid":"30348783","id":"PMC_30348783","title":"SHOC2-MRAS-PP1 complex positively regulates RAF activity and contributes to Noonan syndrome pathogenesis.","date":"2018","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/30348783","citation_count":72,"is_preprint":false},{"pmid":"35831509","id":"PMC_35831509","title":"Structure-function analysis of the SHOC2-MRAS-PP1C holophosphatase complex.","date":"2022","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/35831509","citation_count":65,"is_preprint":false},{"pmid":"31182717","id":"PMC_31182717","title":"SHOC2 phosphatase-dependent RAF dimerization mediates resistance to MEK inhibition in RAS-mutant cancers.","date":"2019","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/31182717","citation_count":65,"is_preprint":false},{"pmid":"23918763","id":"PMC_23918763","title":"Expanding the SHOC2 mutation associated phenotype of Noonan syndrome with loose anagen hair: structural brain anomalies and myelofibrosis.","date":"2013","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/23918763","citation_count":54,"is_preprint":false},{"pmid":"20051520","id":"PMC_20051520","title":"The scaffold protein Shoc2/SUR-8 accelerates the interaction of Ras and Raf.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20051520","citation_count":51,"is_preprint":false},{"pmid":"23076151","id":"PMC_23076151","title":"SHOC2 and CRAF mediate ERK1/2 reactivation in mutant NRAS-mediated resistance to RAF inhibitor.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23076151","citation_count":47,"is_preprint":false},{"pmid":"35768504","id":"PMC_35768504","title":"Structural basis for SHOC2 modulation of RAS signalling.","date":"2022","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/35768504","citation_count":43,"is_preprint":false},{"pmid":"30865892","id":"PMC_30865892","title":"The FBXW7-SHOC2-Raptor Axis Controls the Cross-Talks between the RAS-ERK and mTORC1 Signaling Pathways.","date":"2019","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/30865892","citation_count":43,"is_preprint":false},{"pmid":"35830882","id":"PMC_35830882","title":"Structure of the MRAS-SHOC2-PP1C phosphatase complex.","date":"2022","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/35830882","citation_count":42,"is_preprint":false},{"pmid":"36175670","id":"PMC_36175670","title":"Structure of the SHOC2-MRAS-PP1C complex provides insights into RAF activation and Noonan syndrome.","date":"2022","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/36175670","citation_count":42,"is_preprint":false},{"pmid":"20882035","id":"PMC_20882035","title":"Mutation analysis of the SHOC2 gene in Noonan-like syndrome and in hematologic malignancies.","date":"2010","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/20882035","citation_count":40,"is_preprint":false},{"pmid":"31213532","id":"PMC_31213532","title":"SHOC2 complex-driven RAF dimerization selectively contributes to ERK pathway dynamics.","date":"2019","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/31213532","citation_count":39,"is_preprint":false},{"pmid":"25022756","id":"PMC_25022756","title":"HUWE1 is a molecular link controlling RAF-1 activity supported by the Shoc2 scaffold.","date":"2014","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/25022756","citation_count":35,"is_preprint":false},{"pmid":"26384305","id":"PMC_26384305","title":"Sur8/Shoc2 promotes cell motility and metastasis through activation of Ras-PI3K signaling.","date":"2015","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/26384305","citation_count":32,"is_preprint":false},{"pmid":"20071468","id":"PMC_20071468","title":"Ras and calcium signaling pathways converge at Raf1 via the Shoc2 scaffold protein.","date":"2010","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/20071468","citation_count":32,"is_preprint":false},{"pmid":"25137548","id":"PMC_25137548","title":"A Novel SHOC2 Variant in Rasopathy.","date":"2014","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/25137548","citation_count":31,"is_preprint":false},{"pmid":"20549726","id":"PMC_20549726","title":"Endothelial SUR-8 acts in an ERK-independent pathway during atrioventricular cushion development.","date":"2010","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/20549726","citation_count":31,"is_preprint":false},{"pmid":"31010381","id":"PMC_31010381","title":"The MTORC1-mediated autophagy is regulated by the FBXW7-SHOC2-RPTOR axis.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/31010381","citation_count":30,"is_preprint":false},{"pmid":"26519477","id":"PMC_26519477","title":"Spatial control of Shoc2-scaffold-mediated ERK1/2 signaling requires remodeling activity of the ATPase PSMC5.","date":"2015","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/26519477","citation_count":29,"is_preprint":false},{"pmid":"30808747","id":"PMC_30808747","title":"M-Ras/Shoc2 signaling modulates E-cadherin turnover and cell-cell adhesion during collective cell migration.","date":"2019","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/30808747","citation_count":28,"is_preprint":false},{"pmid":"25123707","id":"PMC_25123707","title":"Severe craniosynostosis with Noonan syndrome phenotype associated with SHOC2 mutation: clinical evidence of crosslink between FGFR and RAS signaling pathways.","date":"2014","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/25123707","citation_count":28,"is_preprint":false},{"pmid":"27574535","id":"PMC_27574535","title":"The function of Shoc2: A scaffold and beyond.","date":"2016","source":"Communicative & integrative biology","url":"https://pubmed.ncbi.nlm.nih.gov/27574535","citation_count":26,"is_preprint":false},{"pmid":"22528146","id":"PMC_22528146","title":"Noonan syndrome due to a SHOC2 mutation presenting with fetal distress and fatal hypertrophic cardiomyopathy in a premature infant.","date":"2012","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/22528146","citation_count":25,"is_preprint":false},{"pmid":"25331583","id":"PMC_25331583","title":"Phenotypic variability associated with the invariant SHOC2 c.4A>G (p.Ser2Gly) missense mutation.","date":"2014","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/25331583","citation_count":25,"is_preprint":false},{"pmid":"21548061","id":"PMC_21548061","title":"Co-occurring SHOC2 and PTPN11 mutations in a patient with severe/complex Noonan syndrome-like phenotype.","date":"2011","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/21548061","citation_count":24,"is_preprint":false},{"pmid":"33526449","id":"PMC_33526449","title":"A Leucine-Rich Repeat Protein Provides a SHOC2 the RAS Circuit: a Structure-Function Perspective.","date":"2021","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/33526449","citation_count":23,"is_preprint":false},{"pmid":"22606262","id":"PMC_22606262","title":"Shoc2 is targeted to late endosomes and required for Erk1/2 activation in EGF-stimulated cells.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22606262","citation_count":23,"is_preprint":false},{"pmid":"31059601","id":"PMC_31059601","title":"Clinical and functional characterization of a novel RASopathy-causing SHOC2 mutation associated with prenatal-onset hypertrophic cardiomyopathy.","date":"2019","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/31059601","citation_count":23,"is_preprint":false},{"pmid":"36420706","id":"PMC_36420706","title":"lncRNA MALAT1 regulates the resistance of breast cancer cells to paclitaxel via the miR-497-5p/SHOC2 axis.","date":"2022","source":"Pharmacogenomics","url":"https://pubmed.ncbi.nlm.nih.gov/36420706","citation_count":23,"is_preprint":false},{"pmid":"23805200","id":"PMC_23805200","title":"Functional Integration of the Conserved Domains of Shoc2 Scaffold.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23805200","citation_count":22,"is_preprint":false},{"pmid":"24458587","id":"PMC_24458587","title":"Hydrops fetalis in a preterm newborn heterozygous for the c.4A>G SHOC2 mutation.","date":"2014","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/24458587","citation_count":22,"is_preprint":false},{"pmid":"22995099","id":"PMC_22995099","title":"Clinical Heterogeneity in two patients with Noonan-like Syndrome associated with the same SHOC2 mutation.","date":"2012","source":"Italian journal of pediatrics","url":"https://pubmed.ncbi.nlm.nih.gov/22995099","citation_count":21,"is_preprint":false},{"pmid":"21732489","id":"PMC_21732489","title":"Sur8/Shoc2 involves both inhibition of differentiation and maintenance of self-renewal of neural progenitor cells via modulation of extracellular signal-regulated kinase signaling.","date":"2011","source":"Stem cells (Dayton, Ohio)","url":"https://pubmed.ncbi.nlm.nih.gov/21732489","citation_count":20,"is_preprint":false},{"pmid":"30657565","id":"PMC_30657565","title":"MiR-299-3p functions as a tumor suppressor in thyroid cancer by regulating SHOC2.","date":"2019","source":"European review for medical and pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/30657565","citation_count":20,"is_preprint":false},{"pmid":"33106373","id":"PMC_33106373","title":"SHOC2 Is a Critical Modulator of Sensitivity to EGFR-TKIs in Non-Small Cell Lung Cancer Cells.","date":"2020","source":"Molecular cancer research : MCR","url":"https://pubmed.ncbi.nlm.nih.gov/33106373","citation_count":19,"is_preprint":false},{"pmid":"39490614","id":"PMC_39490614","title":"Small-molecule targeting BCAT1-mediated BCAA metabolism inhibits the activation of SHOC2-RAS-ERK to induce apoptosis of Triple-negative breast cancer cells.","date":"2024","source":"Journal of advanced research","url":"https://pubmed.ncbi.nlm.nih.gov/39490614","citation_count":18,"is_preprint":false},{"pmid":"27466182","id":"PMC_27466182","title":"SHOC2 subcellular shuttling requires the KEKE motif-rich region and N-terminal leucine-rich repeat domain and impacts on ERK signalling.","date":"2016","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27466182","citation_count":18,"is_preprint":false},{"pmid":"24739123","id":"PMC_24739123","title":"Rare copy number variations containing genes involved in RASopathies: deletion of SHOC2 and duplication of PTPN11.","date":"2014","source":"Molecular cytogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/24739123","citation_count":17,"is_preprint":false},{"pmid":"40335703","id":"PMC_40335703","title":"Targeting the SHOC2-RAS interaction in RAS-mutant cancers.","date":"2025","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/40335703","citation_count":15,"is_preprint":false},{"pmid":"26876614","id":"PMC_26876614","title":"Shoc2-tranduced ERK1/2 motility signals--Novel insights from functional genomics.","date":"2016","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/26876614","citation_count":15,"is_preprint":false},{"pmid":"30329053","id":"PMC_30329053","title":"Hematopoietic and neural crest defects in zebrafish shoc2 mutants: a novel vertebrate model for Noonan-like syndrome.","date":"2019","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30329053","citation_count":15,"is_preprint":false},{"pmid":"30333251","id":"PMC_30333251","title":"Systematic identification of Celastrol-binding proteins reveals that Shoc2 is inhibited by Celastrol.","date":"2018","source":"Bioscience reports","url":"https://pubmed.ncbi.nlm.nih.gov/30333251","citation_count":14,"is_preprint":false},{"pmid":"35348676","id":"PMC_35348676","title":"Expanding the molecular spectrum of pathogenic SHOC2 variants underlying Mazzanti syndrome.","date":"2022","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/35348676","citation_count":13,"is_preprint":false},{"pmid":"35073369","id":"PMC_35073369","title":"Shoc2 recognizes bacterial flagellin and mediates antibacterial Erk/Stat signaling in an invertebrate.","date":"2022","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/35073369","citation_count":13,"is_preprint":false},{"pmid":"36543126","id":"PMC_36543126","title":"The Sag-Shoc2 axis regulates conversion of mPanINs to cystic lesions in Kras pancreatic tumor model.","date":"2022","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/36543126","citation_count":12,"is_preprint":false},{"pmid":"37166421","id":"PMC_37166421","title":"LncRNA FALEC increases the proliferation, migration and drug resistance of cholangiocarcinoma through competitive regulation of miR-20a-5p/SHOC2 axis.","date":"2023","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/37166421","citation_count":11,"is_preprint":false},{"pmid":"31091164","id":"PMC_31091164","title":"VCP/p97 controls signals of the ERK1/2 pathway transmitted via the Shoc2 scaffolding complex: novel insights into IBMPFD pathology.","date":"2019","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/31091164","citation_count":11,"is_preprint":false},{"pmid":"38882927","id":"PMC_38882927","title":"RAS and SHOC2 Roles in RAF Activation and Therapeutic Considerations.","date":"2023","source":"Annual review of cancer biology","url":"https://pubmed.ncbi.nlm.nih.gov/38882927","citation_count":10,"is_preprint":false},{"pmid":"34553755","id":"PMC_34553755","title":"The role of USP7 in the Shoc2-ERK1/2 signaling axis and Noonan-like syndrome with loose anagen hair.","date":"2021","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/34553755","citation_count":8,"is_preprint":false},{"pmid":"27469030","id":"PMC_27469030","title":"Sur8 mediates tumorigenesis and metastasis in colorectal cancer.","date":"2016","source":"Experimental & molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/27469030","citation_count":7,"is_preprint":false},{"pmid":"37074066","id":"PMC_37074066","title":"Structural insights into the role of SHOC2-MRAS-PP1C complex in RAF activation.","date":"2023","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/37074066","citation_count":6,"is_preprint":false},{"pmid":"36265687","id":"PMC_36265687","title":"Shoc2 controls ERK1/2-driven neural crest development by balancing components of the extracellular matrix.","date":"2022","source":"Developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/36265687","citation_count":6,"is_preprint":false},{"pmid":"37170083","id":"PMC_37170083","title":"SHOC2 mediates the drug-resistance of triple-negative breast cancer cells to everolimus.","date":"2023","source":"Cancer biology & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/37170083","citation_count":6,"is_preprint":false},{"pmid":"31710605","id":"PMC_31710605","title":"SUR-8 interacts with PP1-87B to stabilize PERIOD and regulate circadian rhythms in Drosophila.","date":"2019","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/31710605","citation_count":6,"is_preprint":false},{"pmid":"29383184","id":"PMC_29383184","title":"Stabilization of Sur8 via PKCα/δ degradation promotes transformation and migration of colorectal cancer cells.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/29383184","citation_count":5,"is_preprint":false},{"pmid":"31869742","id":"PMC_31869742","title":"Single-domain antibodies for functional targeting of the signaling scaffold Shoc2.","date":"2019","source":"Molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/31869742","citation_count":4,"is_preprint":false},{"pmid":"39871893","id":"PMC_39871893","title":"SHOC2 plays an oncogenic or tumor-suppressive role by differentially targeting the MAPK and mTORC1 signals in liver cancer.","date":"2024","source":"Life medicine","url":"https://pubmed.ncbi.nlm.nih.gov/39871893","citation_count":4,"is_preprint":false},{"pmid":"36579329","id":"PMC_36579329","title":"Case report: A de novo RASopathy-causing SHOC2 variant in a Chinese girl with noonan syndrome-like with loose anagen hair.","date":"2022","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36579329","citation_count":4,"is_preprint":false},{"pmid":"27077079","id":"PMC_27077079","title":"Data set for transcriptional response to depletion of the Shoc2 scaffolding protein.","date":"2016","source":"Data in brief","url":"https://pubmed.ncbi.nlm.nih.gov/27077079","citation_count":4,"is_preprint":false},{"pmid":"25514808","id":"PMC_25514808","title":"Shoc2/Sur8 protein regulates neurite outgrowth.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25514808","citation_count":3,"is_preprint":false},{"pmid":"32938995","id":"PMC_32938995","title":"SHOC2 scaffold protein modulates daunorubicin-induced cell death through p53 modulation in lymphoid leukemia cells.","date":"2020","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/32938995","citation_count":3,"is_preprint":false},{"pmid":"30962759","id":"PMC_30962759","title":"Recurrent Erythema Nodosum in a Child with a SHOC2 Gene Mutation.","date":"2019","source":"Yonago acta medica","url":"https://pubmed.ncbi.nlm.nih.gov/30962759","citation_count":3,"is_preprint":false},{"pmid":"38019730","id":"PMC_38019730","title":"Co-Occurring Thrombotic Thrombocytopenic Purpura and Autoimmune Hemolytic Anemia in a Child Carrying the Pathogenic SHOC2 c.4A>G (p.Ser2Gly) Variant.","date":"2023","source":"The American journal of case reports","url":"https://pubmed.ncbi.nlm.nih.gov/38019730","citation_count":2,"is_preprint":false},{"pmid":"38219533","id":"PMC_38219533","title":"circCPA4 induces malignant behaviors of prostate cancer via miR-491-5p/SHOC2 feedback loop.","date":"2024","source":"Clinics (Sao Paulo, Brazil)","url":"https://pubmed.ncbi.nlm.nih.gov/38219533","citation_count":1,"is_preprint":false},{"pmid":"38881369","id":"PMC_38881369","title":"The expression of congenital Shoc2 variants induces AKT-dependent crosstalk activation of the ERK1/2 pathway.","date":"2024","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/38881369","citation_count":0,"is_preprint":false},{"pmid":"38187642","id":"PMC_38187642","title":"The expression of congenital Shoc2 variants induces AKT-dependent feedback activation of the ERK1/2 pathway.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/38187642","citation_count":0,"is_preprint":false},{"pmid":"40196569","id":"PMC_40196569","title":"Signaling scaffold Shoc2 regulates lymphangiogenesis by suppressing mTORC1-mediated IFN responses.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/40196569","citation_count":0,"is_preprint":false},{"pmid":"35822684","id":"PMC_35822684","title":"The Clinical and Molecular Assessment of Iranian Families with Severe Congenital Neutropenia, Identification of HYOU1 and SHOC2 as Potential Novel Gene Defects.","date":"2022","source":"Iranian journal of allergy, asthma, and immunology","url":"https://pubmed.ncbi.nlm.nih.gov/35822684","citation_count":0,"is_preprint":false},{"pmid":"42185401","id":"PMC_42185401","title":"Expression of LIFR in tumor and SHOC2, YAP1 in plasma mRNA as potential biomarkers in KRAS G12C NSCLC.","date":"2026","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/42185401","citation_count":0,"is_preprint":false},{"pmid":"41946973","id":"PMC_41946973","title":"Signaling scaffold Shoc2 regulates lymphangiogenesis by suppressing mTORC1-mediated IFN responses.","date":"2026","source":"Cell death and differentiation","url":"https://pubmed.ncbi.nlm.nih.gov/41946973","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.01.616145","title":"Injury-induced transcription in the planarian outer epithelium is critical for tissue regeneration","date":"2024-10-03","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.01.616145","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":38097,"output_tokens":8273,"usd":0.119193,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":17973,"output_tokens":5442,"usd":0.112958,"stage2_stop_reason":"end_turn"},"total_usd":0.232151,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"C. elegans SUR-8 (SHOC2 ortholog) acts downstream of or in parallel to RAS but upstream of RAF in the RAS-MAPK pathway, as established by genetic epistasis: sur-8 loss suppresses activated ras and enhances mpk-1/ksr-1 phenotypes. The human SUR-8 homolog directly binds K-Ras and N-Ras but not H-Ras in vitro.\",\n      \"method\": \"Genetic epistasis (suppressor/enhancer screens in C. elegans), direct protein binding assay (in vitro pull-down with RAS isoforms)\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — genetic epistasis in C. elegans plus in vitro binding assay; foundational mechanism paper, replicated by subsequent work\",\n      \"pmids\": [\"9674433\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"SOC-2/SHOC2 encodes a leucine-rich repeat protein functioning downstream of the EGL-15 FGF receptor in C. elegans. Human SHOC-2 protein is cytoplasmically localized. SHOC2 is not observed to be tyrosine phosphorylated in response to FGF stimulation, and phosphorylation of YXNX motifs is not required for SOC-2 function in vivo.\",\n      \"method\": \"Genetic suppressor screen, subcellular localization by immunofluorescence, phosphorylation assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — genetic epistasis plus direct localization experiment, but some findings are negative results; single lab\",\n      \"pmids\": [\"9618511\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Human Sur-8 (SHOC2) forms a ternary complex with Ras and Raf, interacting with both proteins simultaneously. Sur-8 enhances Ras- or EGF-induced Raf and ERK activation but has no effect on ERK activation by active Raf or MEK, and does not increase AKT or JNK activation, placing its action between Ras and Raf.\",\n      \"method\": \"Co-immunoprecipitation, pulldown, overexpression assays with epistasis (active Raf/MEK bypass), kinase activation assays\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP establishing ternary complex, epistasis placing SHOC2 between RAS and RAF, replicated across multiple subsequent studies\",\n      \"pmids\": [\"10783161\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Erbin inhibits ERK activation by disrupting the Sur-8–Ras–Raf complex: Erbin's LRR domain interacts with Sur-8 and reduces Sur-8 binding to active Ras and Raf. Erbin knockdown increases Sur-8–Ras/Raf interaction and ERK activation.\",\n      \"method\": \"Co-immunoprecipitation, Erbin shRNA knockdown, reporter assays, interaction mapping\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — reciprocal Co-IP plus shRNA loss-of-function with defined molecular phenotype; single lab\",\n      \"pmids\": [\"16301319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"SHOC2 (Sur-8) and the catalytic subunit of protein phosphatase 1 (PP1c) form a complex that acts as a highly specific M-Ras effector. This SHOC2-PP1c holoenzyme dephosphorylates the inhibitory S259 site on RAF (bound to M-Ras or Ras), thereby activating RAF and the MAPK pathway. SHOC2 function is essential for MAPK (but not PI3K) pathway activation by growth factors in tumor cells.\",\n      \"method\": \"Proteomics (mass spectrometry), Co-immunoprecipitation, in vitro phosphatase assay, RNAi knockdown with pathway readouts\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — proteomics identification plus in vitro phosphatase assay plus RNAi epistasis; foundational mechanistic discovery, independently replicated\",\n      \"pmids\": [\"16630891\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The disease-causing S2G mutation in SHOC2 introduces an N-myristoylation site (requires N-terminal glycine), causing aberrant constitutive targeting of SHOC2 to the plasma membrane and impaired translocation to the nucleus upon growth factor stimulation. This mislocalization results in cell-type-specific enhancement of MAPK activation.\",\n      \"method\": \"N-myristoylation assay, subcellular fractionation/live imaging, mutant expression in mammalian cells and C. elegans, MAPK activation assays\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct biochemical demonstration of N-myristoylation, subcellular localization experiment with functional consequence, in vivo C. elegans validation; multiple orthogonal methods\",\n      \"pmids\": [\"19684605\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SHOC2 (Shoc2/SUR-8) acts as a scaffold that accelerates both the association and dissociation of Ras–Raf interaction (accelerator model), as demonstrated by FRET biosensor live-cell imaging and computational modeling. SHOC2 knockdown reduces MEK/ERK phosphorylation but not Ras activation.\",\n      \"method\": \"FRET biosensor (live-cell imaging), RNAi knockdown, computational modeling\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — direct live-cell FRET measurement of Ras-Raf interaction kinetics, supported by computational modeling; mechanistically precise, single lab but two complementary orthogonal methods\",\n      \"pmids\": [\"20051520\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Shoc2 scaffold protein is required for Ca²⁺/calmodulin-dependent activation of Raf1 at the plasma membrane downstream of Ras. Ca²⁺-dependent Raf1 activation was abolished by Shoc2 knockdown, demonstrating Shoc2 integrates Ras and Ca²⁺ signaling inputs at Raf1.\",\n      \"method\": \"FRET biosensor, RNAi knockdown, pharmacological manipulation of Ca²⁺/calmodulin, synthetic GEF (eGRF) system\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — FRET-based live imaging plus shRNA epistasis; single lab, two orthogonal methods\",\n      \"pmids\": [\"20071468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Endothelial-specific deletion of SUR-8 in mice causes late embryonic lethality with cardiac defects including hypoplastic endocardial cushions due to reduced endothelial-mesenchymal transformation, but ERK activation is not affected in mutant endothelial cells, indicating SUR-8 acts in an ERK-independent pathway during atrioventricular cushion development.\",\n      \"method\": \"Conditional (endothelial-specific) knockout mouse, histological analysis, ERK activation assays\",\n      \"journal\": \"Developmental dynamics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean conditional KO with defined cellular phenotype and negative ERK activation result; single lab\",\n      \"pmids\": [\"20549726\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Shoc2 localizes to late endosomes (Rab7-positive) upon EGFR activation in a RAS-activity- and clathrin-dependent manner. Endosomal targeting is required for ERK1/2 activation at physiological EGF concentrations. The disease-causing S2G myristoylated mutant is excluded from late endosomes (found on plasma membrane and early endosomes) and fails to rescue ERK1/2 activation in Shoc2-depleted cells.\",\n      \"method\": \"Live-cell imaging (RFP-tagged Shoc2), RNAi (clathrin, H-RAS dominant-negative), rescue experiments, subcellular fractionation\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment with functional consequence (ERK rescue), dominant-negative and RNAi epistasis, multiple orthogonal methods; single lab\",\n      \"pmids\": [\"22606262\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"SHOC2 (Sur-8) and CRAF mediate ERK1/2 reactivation in BRAF(V600E)/NRAS(Q61K) cells during RAF inhibitor treatment. ERK1/2 activation and resistance to apoptosis in these cells require the RAF-binding site of NRAS and are modulated by SHOC-2 expression.\",\n      \"method\": \"siRNA knockdown, kinase activation assays, apoptosis assays, mutant expression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — siRNA knockdown with defined pathway and apoptosis phenotype; single lab, two orthogonal readouts\",\n      \"pmids\": [\"23076151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"SHOC2 forms a macromolecular complex with MRAS and SCRIB. SCRIB functions as a PP1-regulatory protein and antagonizes SHOC2-mediated RAF dephosphorylation through competition for PP1 molecules within the same complex. SHOC2 function is selectively required for malignant properties of RAS-mutant tumor cells; MRAS and SHOC2 play a key role in polarized migration.\",\n      \"method\": \"Co-immunoprecipitation, mass spectrometry, shRNA knockdown, RAF dephosphorylation assay, migration assays\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — MS-identified complex, Co-IP, in vitro phosphatase competition assay, loss-of-function phenotype; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"24211266\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"SHOC2 has two main structural domains: an N-terminal non-LRR domain mediating binding to both M-Ras and Raf-1, and a C-terminal LRR region containing a late endosomal targeting motif. M-Ras binding to Shoc2 is independent of M-Ras GTPase activity.\",\n      \"method\": \"Domain deletion/mutation analysis, Co-immunoprecipitation, rescue experiments in Shoc2-depleted cells\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — systematic domain-mapping by Co-IP and rescue; single lab, multiple domain constructs tested\",\n      \"pmids\": [\"23805200\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"A novel SHOC2 mutation (M173I) causes a Rasopathy by impairing SHOC2 binding to PP1c, leading to insufficient RAF-1 kinase activation and failure to fully rescue ERK1/2 activity in SHOC2-depleted cells.\",\n      \"method\": \"Co-immunoprecipitation, rescue assay in SHOC2-depleted cells, ERK1/2 phosphorylation assay\",\n      \"journal\": \"Human mutation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — Co-IP and functional rescue assay with clear mechanistic consequence; single lab\",\n      \"pmids\": [\"25137548\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"HUWE1 E3 ubiquitin ligase is a binding partner and regulator of Shoc2: HUWE1 mediates ubiquitination of Shoc2 (controlling Shoc2 levels) and also controls ubiquitination and levels of RAF-1 within the Shoc2 complex. HUWE1-mediated Shoc2 ubiquitination acts as a switch regulating RAF-1 kinase activity transition from active to inactive state.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, siRNA knockdown, ERK1/2 pathway activation assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — Co-IP, ubiquitination assay, and knockdown with pathway readout; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"25022756\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The AAA+ ATPase PSMC5 is a binding partner of Shoc2 that triggers Shoc2 translocation to endosomes. At endosomes, PSMC5 displaces HUWE1 from the Shoc2 scaffold complex, attenuating ubiquitylation of both Shoc2 and RAF-1. The Noonan-like S2G mutation alters Shoc2 subcellular distribution, reducing PSMC5 accessibility and thereby altering Shoc2 ubiquitylation.\",\n      \"method\": \"Co-immunoprecipitation, subcellular fractionation/live imaging, ubiquitylation assays, knockdown experiments\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — Co-IP plus localization experiment with functional ubiquitylation consequence; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"26519477\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Sur8/Shoc2 interacts with the p110α subunit of PI3K (in addition to Ras and Raf), with interactions increased in an EGF- and oncogenic Ras-dependent manner. Sur8 regulates cell migration and invasion via PI3K-dependent Rac activation and MMP upregulation.\",\n      \"method\": \"Co-immunoprecipitation, kinase inhibitor experiments, migration/invasion assays, lentiviral knockdown\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP establishing new binding partner, pharmacological epistasis, loss-of-function with migration phenotype; single lab\",\n      \"pmids\": [\"26384305\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"SHOC2 nuclear-cytoplasmic shuttling requires LRRs 1–13 for nuclear import and constitutive plasma membrane targeting of S2G, while the KEKE motif-rich N-terminal region is necessary for efficient nuclear export. SHOC2 trapping at different subcellular compartments has distinct impacts on ERK signaling strength and dynamics, suggesting a dual modulatory role at different intracellular sites.\",\n      \"method\": \"Domain deletion/mutation constructs, live-cell imaging, subcellular fractionation, ERK activation assays\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — systematic domain mapping with localization and functional ERK readouts; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"27466182\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"PKCα and PKCδ phosphorylate Sur8 at Thr-71 and Ser-297, respectively, promoting polyubiquitin-dependent degradation of Sur8. FGF2 stabilizes Sur8 by reducing this PKC-mediated phosphorylation and degradation.\",\n      \"method\": \"Phosphorylation mutagenesis, ubiquitination assays, kinase activity assays, co-immunoprecipitation\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — site-specific mutagenesis and ubiquitination assay identifying specific phosphorylation sites; single lab\",\n      \"pmids\": [\"29383184\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"The MRAS-SHOC2-PP1 heterotrimeric holoenzyme dephosphorylates the inhibitory S259 site on RAF kinases; MRAS and SHOC2 function as PP1 regulatory subunits conferring striking substrate specificity toward RAF. Membrane localization of MRAS is required for efficient RAF dephosphorylation in cells. SHOC2's predicted structure resembles the A subunit of PP2A. Multiple SHOC2 regions and MRAS switch I/interswitch residues mediate complex formation. Noonan syndrome mutations in SHOC2, MRAS, and PPP1CB invariably promote ternary complex formation.\",\n      \"method\": \"In vitro phosphatase assay, Co-immunoprecipitation, membrane targeting experiments, mutagenesis, structural prediction\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro phosphatase reconstitution, mutagenesis, multiple orthogonal methods; replicated by subsequent structural papers\",\n      \"pmids\": [\"30348783\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SHOC2 complex (SHOC2-MRAS-PP1)-mediated S259 RAF dephosphorylation is critically required for growth factor-induced RAF heterodimerization and MEK dissociation from BRAF. SHOC2 is essential for a rapid transient phase of ERK activation induced by EGF, while a slow sustained phase driven by palmitoylated H/N-RAS and CRAF is SHOC2-independent. KRAS mutant cells preferentially rely on SHOC2 for ERK signaling under anchorage-independent conditions.\",\n      \"method\": \"SHOC2 knockout/knockdown, RAF dimerization assays, MEK co-immunoprecipitation, ERK activation time-course, anchorage-independent growth assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — KO with multiple defined molecular phenotypes (RAF dimerization, MEK dissociation, ERK kinetics) using multiple orthogonal methods; context-dependent epistasis established\",\n      \"pmids\": [\"31213532\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SHOC2 deletion prevents MEKi-induced RAF dimerization, leading to more potent and durable ERK pathway suppression and BIM-dependent apoptosis. Systemic SHOC2 ablation in adult mice is relatively well tolerated. SHOC2 deletion selectively sensitizes KRAS- and EGFR-mutant NSCLC cells to MEK inhibitors.\",\n      \"method\": \"Genetic SHOC2 knockout (CRISPR), murine autochthonous cancer models, RAF dimerization assays, apoptosis assays (BIM), combination drug treatment\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR KO with defined RAF dimerization mechanism, in vivo mouse model, apoptosis mechanistic readout; single lab with multiple orthogonal methods\",\n      \"pmids\": [\"31182717\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SHOC2 is a substrate of the FBXW7 E3 ubiquitin ligase. Growth stimuli trigger SHOC2 phosphorylation on Thr507 by the MAPK signal, which facilitates FBXW7 binding for ubiquitylation and degradation, establishing a negative feedback loop. Additionally, SHOC2 selectively binds Raptor (mTORC1 component) to competitively inhibit Raptor-mTOR binding, inactivating mTORC1 and inducing autophagy; Raptor binding to SHOC2 inhibits SHOC2-RAS binding to block MAPK signaling.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, phosphorylation site mapping/mutagenesis (Thr507), mTORC1 activity assays, competitive binding assays\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — Co-IP, ubiquitination assay, phospho-site mutagenesis, and competition assay; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"30865892\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"M-Ras/Shoc2 signaling contributes to E-cadherin/p120-catenin junction turnover required for collective cell migration. Activated M-Ras recruits Shoc2 to cell surface junctions. Loss of Shoc2 reduces junction turnover and impairs collective migration. The regulatory effect requires downstream ERK cascade activation and involves phosphoregulation of p120-catenin. The myristoylated Shoc2 S2G Noonan mutant causes gain-of-function increased junction turnover and less cohesive migration.\",\n      \"method\": \"Dominant-negative M-Ras expression, SHOC2 knockdown/reconstitution, E-cadherin/p120-catenin co-immunoprecipitation, live-cell imaging of junction dynamics, zebrafish embryo gastrulation assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — depletion/reconstitution with multiple orthogonal methods (Co-IP, live imaging, in vivo zebrafish), mechanistic pathway placement via ERK epistasis; single lab\",\n      \"pmids\": [\"30808747\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"VCP/p97 ATPase activity controls stoichiometry of HUWE1 in the Shoc2 complex and modulates HUWE1-mediated allosteric ubiquitination of Shoc2 and RAF-1. Abrogated VCP ATPase activity augments Shoc2/RAF-1 ubiquitination and alters RAF-1 phosphorylation and ERK1/2 signaling. Fibroblasts from IBMPFD patients with germline VCP mutations show imbalanced Shoc2 ubiquitination and ERK1/2 phosphorylation.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, VCP ATPase mutant expression, patient-derived fibroblasts\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — Co-IP and ubiquitination assay with ATPase mutant and patient cells; single lab, two orthogonal approaches\",\n      \"pmids\": [\"31091164\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"USP7, a ubiquitin-specific protease, interacts with Shoc2 in an ERK1/2-activation-dependent manner. Within the Shoc2 module, USP7 functions as a molecular 'switch' controlling HUWE1 E3 ligase activity and the HUWE1-induced regulatory feedback loop. Disruption of Shoc2-USP7 binding leads to aberrant ERK1/2 axis activation.\",\n      \"method\": \"Co-immunoprecipitation, USP7 knockdown/inhibition, ERK1/2 activation assays, HUWE1 activity assays\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — Co-IP with pathway-dependent timing, loss-of-function with defined molecular phenotype; single lab\",\n      \"pmids\": [\"34553755\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Cryo-EM structures of the SHOC2-MRAS-PP1C complex (two independent studies, ~3 Å resolution) reveal a tripartite architecture: crescent-shaped SHOC2 acts as a cradle bridging PP1C and MRAS through its concave LRR surface. SHOC2 also engages PP1C through an N-terminal disordered region containing a cryptic RVXF motif. Complex assembly is initiated by SHOC2-PP1C interaction and stabilized by GTP-loaded MRAS. RASopathy mutations reside at protein-protein interfaces and enhance holoenzyme affinity. Deep mutational scanning comprehensively maps functional residues of SHOC2. Multiple RAS isoforms can substitute for MRAS in a GTP-dependent manner.\",\n      \"method\": \"Cryo-electron microscopy, X-ray crystallography, deep mutational scanning, biophysical binding assays, mutagenesis\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — atomic-resolution cryo-EM structure plus deep mutational scanning plus biophysical validation; replicated by three independent structural studies in the same year\",\n      \"pmids\": [\"35831509\", \"35768504\", \"35830882\", \"36175670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Crystal structure of the SHOC2-MRAS-PP1C complex shows all three proteins synergistically interact with each other. PP1C substrate specificity toward RAF is enhanced upon interaction with both SHOC2 and MRAS. Complex forms only when MRAS is GTP-bound. SHOC2 functions as scaffolding protein bringing PP1C and MRAS together. Noonan syndrome mutations enhance complex formation.\",\n      \"method\": \"X-ray crystallography, in vitro phosphatase assay with RAF substrates, biophysical binding assays, mutagenesis\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus in vitro reconstituted phosphatase activity assay with mutagenesis; independent replication of related structures\",\n      \"pmids\": [\"36175670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NRAS(Q61R) forms a direct protein-protein interaction with SHOC2, revealed by X-ray co-crystal structure. SHOC2 is a dependency of RAS(Q61*) tumors in a nucleotide-state-dependent manner. Small molecules disrupting the SHOC2–RAS(Q61*) interaction inhibit MAPK signaling and proliferation in RAS-mutant cancer models.\",\n      \"method\": \"X-ray co-crystallography, CRISPR dependency screens, in vitro high-throughput small-molecule screening, MAPK signaling assays, proliferation assays\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — X-ray co-crystal structure establishing direct interaction, corroborated by pharmacological disruption and genetic dependency; multiple orthogonal methods\",\n      \"pmids\": [\"40335703\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In cells expressing NSLH-associated Shoc2 variants, when both AKT and ERK1/2 pathways are activated downstream of EGFR, AKT signaling triggers PAK activation followed by Raf-1/MEK1/2 phosphorylation and ERK1/2 activation, revealing a previously unrecognized AKT-PAK-RAF feedback crosstalk. In contrast, when ERK1/2 is the primary EGFR effector, Shoc2 variants cannot upregulate ERK1/2 to wild-type levels.\",\n      \"method\": \"Mutant expression/reconstitution, pathway inhibitor epistasis, ERK1/2 and AKT phosphorylation assays\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — mutant reconstitution plus pharmacological epistasis identifying novel feedback; single lab, two orthogonal methods\",\n      \"pmids\": [\"38881369\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Loss of Shoc2 in zebrafish and lymphatic endothelial cells results in near-complete loss of lymphatic vasculature and cellular senescence. Mechanistically, Shoc2 loss increases mTORC1 signaling, impairs mitochondrial respiration, and triggers an IRF/IFN-II innate immune response leading to senescence. The NSLH-causing S2G variant phenocopies Shoc2 loss in this context.\",\n      \"method\": \"Zebrafish genetic loss-of-function, in vitro lymphatic endothelial cell assays, mTORC1 activity assays, mitochondrial respiration assay, IFN pathway assays\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo and in vitro loss-of-function with multiple mechanistic readouts; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"41946973\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SHOC2 is a leucine-rich repeat scaffold protein that forms a heterotrimeric holophosphatase complex with M-RAS (GTP-bound) and PP1C; within this complex—whose atomic structure has been determined by cryo-EM and X-ray crystallography—SHOC2 bridges PP1C and M-RAS through its concave LRR surface and an N-terminal RVXF motif to dephosphorylate the inhibitory S259 site on RAF kinases, thereby promoting RAF heterodimerization, MEK/ERK pathway activation, and normal development; its scaffold function is spatiotemporally regulated by PSMC5-dependent endosomal translocation, HUWE1- and FBXW7-mediated ubiquitination/degradation, USP7-controlled deubiquitination, and PKC-mediated phospho-degron formation, while the disease-associated S2G mutation aberrantly N-myristoylates SHOC2 to the plasma membrane, preventing endosomal targeting and dysregulating ERK signaling dynamics.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SHOC2 is a leucine-rich repeat scaffold protein that positions RAS-family GTPases for activation of the RAF–MEK–ERK cascade, acting genetically downstream of RAS but upstream of RAF [#0, #2]. Its central biochemical function is as the scaffolding subunit of a heterotrimeric holophosphatase formed with GTP-loaded M-RAS and the catalytic subunit of protein phosphatase 1 (PP1C); within this complex SHOC2 confers RAF substrate specificity, and the holoenzyme dephosphorylates the inhibitory S259 site on RAF kinases to relieve autoinhibition [#4, #19]. Cryo-EM and crystal structures show that crescent-shaped SHOC2 cradles PP1C and M-RAS through its concave LRR surface and an N-terminal disordered RVXF motif, with assembly initiated by SHOC2–PP1C binding and stabilized only when M-RAS (or substituting RAS isoforms) is GTP-bound [#26, #27]. This S259 dephosphorylation licenses growth factor-induced RAF heterodimerization and MEK release from BRAF, and SHOC2 is selectively required for the rapid transient phase of ERK activation and for ERK signaling in RAS-mutant cells under anchorage-independent conditions [#19, #20]. SHOC2 scaffold activity is spatiotemporally controlled: EGFR/RAS-driven, clathrin-dependent translocation to Rab7 late endosomes is required for ERK activation, and a ubiquitination cycle involving HUWE1, FBXW7, the PSMC5 ATPase, and USP7 tunes SHOC2 and RAF-1 levels and signaling output [#9, #14, #15, #22, #25]. Loss of SHOC2 prevents MEK-inhibitor-induced RAF dimerization and selectively sensitizes KRAS- and EGFR-mutant tumors to MEK inhibition, while direct SHOC2–RAS(Q61) interaction makes it a druggable dependency in RAS(Q61)-mutant cancers [#21, #28]. Gain-of-function in this scaffold underlies Noonan-like RASopathy: the S2G mutation introduces an N-myristoylation site that mistargets SHOC2 to the plasma membrane and excludes it from late endosomes, dysregulating ERK dynamics, and RASopathy mutations in SHOC2, MRAS, and PPP1CB invariably enhance ternary complex formation [#5, #9, #19].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established where SHOC2 acts in the RAS-MAPK pathway, placing it downstream of RAS and upstream of RAF rather than as a generic adaptor.\",\n      \"evidence\": \"Genetic epistasis in C. elegans plus in vitro RAS-isoform binding assays for the human ortholog\",\n      \"pmids\": [\"9674433\", \"9618511\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the biochemical activity of the complex\", \"Mechanism of how SUR-8 couples RAS to RAF unresolved\", \"Isoform selectivity (K/N-RAS vs H-RAS) not mechanistically explained\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Showed SHOC2 forms a ternary complex bridging RAS and RAF simultaneously and enhances RAS/EGF-induced RAF–ERK activation, supporting a scaffold model acting between RAS and RAF.\",\n      \"evidence\": \"Reciprocal Co-IP and kinase activation assays with active RAF/MEK bypass\",\n      \"pmids\": [\"10783161\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No enzymatic activity attributed to the complex\", \"Did not identify additional subunits\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Defined the molecular function of the complex: SHOC2–PP1C is an M-RAS effector holophosphatase that dephosphorylates the inhibitory S259 RAF site to activate MAPK.\",\n      \"evidence\": \"Mass spectrometry, in vitro phosphatase assay, and RNAi with pathway readouts\",\n      \"pmids\": [\"16630891\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of substrate specificity unknown\", \"How PP1C is targeted specifically to RAF unresolved at the time\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Connected SHOC2 to RASopathy disease by showing the S2G mutation creates an N-myristoylation site causing aberrant plasma membrane targeting and dysregulated MAPK activation.\",\n      \"evidence\": \"N-myristoylation assay, subcellular localization, mutant expression in cells and C. elegans\",\n      \"pmids\": [\"19684605\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish the normal localization signal mislocalized by S2G\", \"Cell-type specificity of MAPK enhancement not mechanistically explained\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Provided kinetic and signaling-integration detail: SHOC2 accelerates RAS–RAF association/dissociation and integrates Ca2+/calmodulin inputs at RAF1.\",\n      \"evidence\": \"Live-cell FRET biosensors, computational modeling, RNAi, and pharmacological Ca2+ manipulation\",\n      \"pmids\": [\"20051520\", \"20071468\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Single lab for the accelerator model\", \"Relationship between scaffold kinetics and the holophosphatase activity not reconciled\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed that SHOC2 endosomal trafficking is functionally required, localizing to Rab7 late endosomes in a RAS- and clathrin-dependent manner to drive ERK activation, which the S2G mutant fails to do.\",\n      \"evidence\": \"Live-cell imaging, RNAi/dominant-negative epistasis, and rescue experiments\",\n      \"pmids\": [\"22606262\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of endosomal targeting machinery not fully defined\", \"Whether holophosphatase activity occurs at endosomes unresolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified SCRIB as a competing PP1-regulatory antagonist within the SHOC2 complex and mapped SHOC2 domains, establishing competitive regulation of RAF dephosphorylation.\",\n      \"evidence\": \"MS, Co-IP, in vitro phosphatase competition, and domain deletion analysis\",\n      \"pmids\": [\"24211266\", \"23805200\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Domain assignments later refined by structural work\", \"Physiological contexts where SCRIB competition dominates not defined\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Established ubiquitin-mediated control of the scaffold: HUWE1 ubiquitinates SHOC2 and RAF-1 as a switch for RAF activity, and a RASopathy M173I mutation impairing PP1C binding causes insufficient RAF activation.\",\n      \"evidence\": \"Co-IP, ubiquitination assays, siRNA, and rescue/ERK assays\",\n      \"pmids\": [\"25022756\", \"25137548\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab HUWE1 findings\", \"Spatial coordination of ubiquitination with endosomal targeting unclear\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Connected trafficking and turnover by showing PSMC5 drives SHOC2 endosomal translocation and displaces HUWE1 to attenuate ubiquitylation, with S2G disrupting this regulation.\",\n      \"evidence\": \"Co-IP, live imaging, and ubiquitylation assays with knockdowns\",\n      \"pmids\": [\"26519477\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Mechanism of PSMC5-mediated HUWE1 displacement not structurally defined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identified PKC-dependent phospho-degron formation (Thr-71, Ser-297) promoting SHOC2 degradation, with FGF2 stabilizing SHOC2 by reducing this phosphorylation.\",\n      \"evidence\": \"Site-specific mutagenesis, ubiquitination and kinase assays, Co-IP\",\n      \"pmids\": [\"29383184\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"E3 ligase coupling these sites to degradation not defined here\", \"Single lab\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Resolved the downstream signaling consequence and therapeutic relevance: SHOC2-mediated S259 dephosphorylation licenses RAF heterodimerization and MEK release, governs transient ERK kinetics, and its loss sensitizes KRAS/EGFR-mutant tumors to MEK inhibition.\",\n      \"evidence\": \"SHOC2 KO/knockdown, RAF dimerization and MEK Co-IP assays, ERK time-courses, murine cancer models, and apoptosis assays\",\n      \"pmids\": [\"31213532\", \"31182717\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of RAF specificity not yet resolved\", \"Context-dependence across RAS isoforms incompletely mapped\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Expanded SHOC2 regulation and outputs beyond MAPK: FBXW7-mediated negative feedback via Thr507 phosphorylation, mTORC1 inhibition via Raptor competition, junction-turnover control of collective migration, and VCP/p97 tuning of HUWE1 stoichiometry.\",\n      \"evidence\": \"Co-IP, ubiquitination/phospho-site mutagenesis, competition and mTORC1 assays, junction live imaging, zebrafish, and patient fibroblasts\",\n      \"pmids\": [\"30865892\", \"30808747\", \"31091164\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"mTORC1/Raptor and MAPK roles not integrated mechanistically\", \"Several findings single-lab\", \"Physiological weighting of these alternate functions unclear\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified USP7 as a deubiquitinase switch acting in an ERK-activation-dependent manner to control HUWE1 activity within the SHOC2 module.\",\n      \"evidence\": \"Co-IP, USP7 knockdown/inhibition, and ERK/HUWE1 activity assays\",\n      \"pmids\": [\"34553755\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"How USP7 timing couples to endosomal/PSMC5 events unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Provided atomic-resolution architecture of the SHOC2–MRAS–PP1C holoenzyme, showing SHOC2 cradles PP1C and MRAS via its concave LRR surface and an N-terminal RVXF motif, with GTP-MRAS-dependent assembly and RASopathy mutations enhancing affinity.\",\n      \"evidence\": \"Cryo-EM, X-ray crystallography, deep mutational scanning, and biophysical/phosphatase assays across independent studies\",\n      \"pmids\": [\"35831509\", \"35768504\", \"35830882\", \"36175670\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural state of RAF substrate engagement not captured\", \"Endosomal/regulatory context not in the structures\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrated a direct druggable SHOC2–RAS(Q61) interface and a novel AKT-PAK-RAF feedback route used by RASopathy variants, advancing both therapeutic targeting and disease mechanism.\",\n      \"evidence\": \"X-ray co-crystallography, CRISPR dependency screens, small-molecule screening, and pathway-inhibitor epistasis\",\n      \"pmids\": [\"40335703\", \"38881369\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generality of the AKT-PAK-RAF crosstalk beyond variant cells unclear\", \"In vivo efficacy/selectivity of SHOC2–RAS disruptors not established here\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked SHOC2 to lymphatic development and cellular homeostasis via mTORC1, mitochondrial respiration, and an IRF/IFN-II senescence program, with S2G phenocopying loss.\",\n      \"evidence\": \"Zebrafish and lymphatic endothelial cell loss-of-function with mTORC1, respiration, and IFN pathway assays\",\n      \"pmids\": [\"41946973\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Connection between MAPK/holophosphatase function and the senescence phenotype not mechanistically bridged\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How SHOC2's distinct activities — endosomal scaffolding, the ternary holophosphatase, ubiquitin/phospho regulatory cycles, and mTORC1/migration/senescence outputs — are spatiotemporally coordinated within a single cell remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model integrating trafficking, holophosphatase assembly, and turnover\", \"Relative contribution of MAPK-independent functions to development unquantified\", \"Structural capture of the SHOC2 complex engaging RAF substrate is lacking\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 4, 26, 27]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 11, 19]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [4, 19, 27]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 2, 28]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [9, 15]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [5, 7, 23]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [5, 17]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 4, 19, 20]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [5, 13, 19, 28]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [8, 23, 30]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [22]}\n    ],\n    \"complexes\": [\n      \"SHOC2-MRAS-PP1C holophosphatase\"\n    ],\n    \"partners\": [\n      \"MRAS\",\n      \"PPP1CB\",\n      \"RAF1\",\n      \"SCRIB\",\n      \"HUWE1\",\n      \"FBXW7\",\n      \"USP7\",\n      \"PSMC5\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}