| 1995 |
Numb protein localizes asymmetrically during cell division and segregates into one daughter cell, where it is required for specification of correct cell fate. Its localization is coupled to mitosis, correlated with centrosome position, and is independent of microtubules and actin. |
Genetic loss-of-function, cytochalasin D treatment, nocodazole treatment, immunolocalization in Drosophila neuroblasts |
Nature |
High |
7566172
|
| 2000 |
Numb is an endocytic protein that localizes to endocytic organelles, is co-trafficked with internalizing receptors, and associates with the appendage domain of alpha-adaptin (a subunit of AP2/clathrin-coated pits). Dominant-negative Numb fragments inhibit both constitutive and ligand-regulated receptor-mediated internalization. |
Subcellular fractionation, co-immunoprecipitation with alpha-adaptin, dominant-negative overexpression, receptor internalization assays |
The Journal of cell biology |
High |
11121447
|
| 2002 |
In Drosophila sensory organ precursor cells, Numb acts by polarizing the distribution of alpha-Adaptin (required for receptor-mediated endocytosis). Alpha-Adaptin binds to Numb and localizes asymmetrically in a Numb-dependent fashion. Mutant alpha-Adaptin unable to bind Numb fails to localize asymmetrically and causes numb-like fate defects. Numb also binds the intracellular domain of Notch. |
Co-immunoprecipitation, genetic loss-of-function, binding-deficient mutant analysis, asymmetric division assay in Drosophila SOPs |
Developmental cell |
High |
12194853
|
| 2003 |
Mammalian Numb promotes ubiquitination of membrane-bound Notch1 receptor via its PTB domain, resulting in degradation of the Notch1 intracellular domain and loss of Notch-dependent transcriptional activation. Numb interacts with the HECT domain E3 ligase Itch, and Numb and Itch act cooperatively to ubiquitinate membrane-tethered Notch1. |
Co-immunoprecipitation, ubiquitination assay, Hes1-luciferase reporter assay, PTB domain mutant analysis |
The Journal of biological chemistry |
High |
12682059
|
| 2003 |
Human Numb is a substrate of MDM2 ubiquitin ligase; recombinant hNumb binds MDM2 in vitro and is ubiquitinated by MDM2 in an E1/E2/MDM2-dependent manner requiring the RING-finger domain. Co-transfection of hNumb and MDM2 in U2OS cells leads to Numb ubiquitination and degradation. |
In vitro ubiquitination assay with recombinant proteins, co-immunoprecipitation, co-transfection with RING-finger mutant MDM2 |
Biochemical and biophysical research communications |
High |
12646252
|
| 2003 |
CRMP-2 interacts with Numb, and the CRMP-2/Numb complex localizes to axonal growth cones where Numb associates with L1 (a neuronal adhesion molecule undergoing endocytosis). Dominant-negative CRMP-2 or CRMP-2 siRNA inhibits endocytosis of L1 at growth cones and suppresses axon growth. |
Co-immunoprecipitation, colocalization by immunofluorescence, dominant-negative overexpression, siRNA knockdown, L1 endocytosis assay |
Nature cell biology |
High |
12942088
|
| 2005 |
In Drosophila SOP cells, Numb induces endocytosis of Sanpodo (a four-pass transmembrane protein that enables Notch signaling) via alpha-Adaptin-dependent clathrin-mediated endocytosis. Numb binds Sanpodo through its PTB domain. In numb or alpha-adaptin mutants, Sanpodo is not endocytosed. Numb regulates this endocytosis throughout the cell cycle, not only after division. |
Genetic loss-of-function (numb, alpha-adaptin mutants), co-localization with Rab5/Rab7 endosomal markers, PTB domain binding assay, Drosophila SOP imaging |
EMBO reports |
High |
16113648
|
| 2007 |
Numb is an endocytic adaptor required for directional integrin endocytosis during cell migration. Numb binds integrin-beta subunits and localizes to clathrin-coated structures at the leading edge. RNAi knockdown of Numb impairs integrin endocytosis and directional cell migration. aPKC phosphorylates Numb, releasing it from clathrin-coated structures and preventing integrin binding. Numb interacts with the aPKC-binding partner PAR-3. |
RNAi knockdown, co-immunoprecipitation, live-cell and fixed immunofluorescence, integrin endocytosis assay, phosphorylation assay |
Developmental cell |
High |
17609107
|
| 2008 |
NUMB enters a tricomplex with p53 and the E3 ubiquitin ligase HDM2/MDM2, thereby preventing ubiquitination and degradation of p53. This results in increased p53 protein levels and activity, and regulation of p53-dependent phenotypes. The PTB domain of NUMB is required for this function. |
Co-immunoprecipitation (tricomplex), ubiquitination assay, p53 stability/activity assays, domain mapping, breast cancer cell lines |
Nature |
High |
18172499
|
| 2009 |
Mammalian Notch1 is constitutively internalized and trafficked to recycling and late endosomal compartments. Numb overexpression promotes sorting of Notch1 to late endosomes for degradation; Numb depletion facilitates Notch1 recycling. Numb mutants lacking Itch interaction or endocytic protein-binding motifs fail to promote Notch1 degradation. |
Fluorescence microscopy of endosomal trafficking, Numb knockdown/overexpression, Numb mutant analysis, co-immunoprecipitation with Itch |
The Journal of biological chemistry |
High |
19567869
|
| 2009 |
Numb interacts with E-cadherin through its PTB domain and regulates E-cadherin localization at lateral cell-cell junctions. Numb also binds Par3 in polarized MDCK cells. After Src activation or HGF treatment, Numb dissociates from E-cadherin/Par3 and associates preferentially with aPKC-Par6, sequestering aPKC in the cytosol. Numb knockdown causes basolateral-to-apicolateral E-cadherin translocation, elevated actin polymerization, decreased cell-cell adhesion, and increased migration. |
Co-immunoprecipitation, shRNA knockdown, confocal microscopy, cell scattering assay, E-cadherin localization |
The EMBO journal |
High |
19609305
|
| 2011 |
Numb directly interacts with p120 catenin (which is bound to E-cadherin and prevents its internalization). Numb accumulates at intercellular adhesion sites; its depletion impairs E-cadherin internalization while p120 depletion accelerates it. aPKC phosphorylates Numb and inhibits its association with p120 and alpha-adaptin, thereby attenuating E-cadherin endocytosis. A phosphomimetic Numb mutant or an alpha-adaptin-binding-deficient mutant fails to restore E-cadherin internalization. |
Co-immunoprecipitation, RNAi depletion, phosphomimetic/binding-deficient mutant analysis, E-cadherin internalization assay, aPKC kinase assay |
Molecular biology of the cell |
High |
21775625
|
| 2012 |
MDM2 uses a dual-site mechanism (N-terminal hydrophobic pocket and acidic domain) to bind and ubiquitinate NUMB, analogous to its interaction with p53. Only one region within the PTB domain of NUMB (amino acids 113–148) mediates binding to both MDM2 domains. By binding to both MDM2 domains, NUMB disrupts the MDM2-p53 complex and inhibits MDM2-catalyzed ubiquitination of p53. |
In vitro binding assays, ubiquitination assay, domain deletion and point-mutant analysis, co-immunoprecipitation |
The Journal of biological chemistry |
High |
22337874
|
| 2012 |
Numb knockdown causes G2/M arrest and reduced cell growth in melanoma cells. Numb co-immunoprecipitates with and colocalizes with polo-like kinase Plk1; Numb cycles in a cell-cycle-dependent manner with Plk1. Numb expression is required for Plk1 protein stability and proper localization to spindle poles during mitosis. Numb reduction leads to mislocalized Plk1 and disorganized gamma-tubulin at centrosomes. |
Co-immunoprecipitation, colocalization, siRNA knockdown, cell cycle analysis, immunofluorescence of spindle poles |
Cancer research |
Medium |
22593191
|
| 2011 |
All four Numb isoforms negatively regulate Notch1 in transcription and myogenic differentiation assays. Notch3 is not polyubiquitinated nor degraded when co-expressed with Numb. Unlike Notch1, Notch3 is not a target of Numb-mediated ubiquitination, demonstrating receptor-specific regulation. |
Transcription reporter assay, myogenic differentiation assay, ubiquitination assay with co-expressed proteins |
Mechanisms of development |
Medium |
21356309
|
| 2013 |
In cardiac development, NUMB and NUMBL are required for downregulation of ERBB2 signaling by promoting ERBB2 transition from early to late endosomes for degradation via interaction with the small GTPase Rab7. Loss of NUMB/NUMBL causes a partial block of late endosome formation, sustained ERBB2/STAT5 signaling, YAP1 nuclear localization, and aberrant cardiomyocyte proliferation resulting in ventricular noncompaction. |
Cardiac-specific double knockout, endosomal fractionation, co-immunoprecipitation with Rab7, rescue by heterozygous ERBB2 or YAP1 loss-of-function |
The Journal of clinical investigation |
High |
28067668
|
| 2018 |
Numb PTB domain, using two distinct binding surfaces, recognizes repeating motifs within Pon in a multivalent manner. This multivalent Numb-Pon interaction leads to liquid-liquid phase separation of the complex, forming basal condensates in Drosophila neuroblasts. Perturbation of this phase transition impairs basal localization of Numb and subsequent suppression of Notch signaling during asymmetric neuroblast division. |
Crystal structure/structural analysis of PTB-Pon interaction, in vitro phase separation assay, mutagenesis of binding surfaces, Drosophila live imaging of Numb localization |
Nature communications |
High |
29467404
|
| 2018 |
Numb depletion from proximal tubules promotes mitochondrial fragmentation by increasing phosphorylation of Drp1 at Ser637 (mouse Ser656), which recruits Drp1 to mitochondria. ROCK kinase inhibition (Y-27632) attenuates Drp1 phosphorylation and fragmentation in Numb-deficient cells. Drp1 inhibitor mdivi-1 restores mitochondrial morphology in Numb-KO mice. |
Proximal tubule-specific Numb KO mice, phospho-Drp1 western blot, ROCK inhibitor treatment, Drp1 inhibitor rescue, electron microscopy |
Antioxidants & redox signaling |
Medium |
29890853
|
| 2017 |
NUMB and NUMBL interact with VEGFR2 and VEGFR3, controlling VEGF receptor endocytosis, signaling activation, and recycling back to the plasma membrane. Inducible endothelial-specific inactivation of Numb/Numbl impairs vessel growth, reduces endothelial proliferation/sprouting, and decreases VEGF receptor activation. |
Co-immunoprecipitation with VEGFR2/3, inducible endothelial-specific KO mice, receptor recycling assay, retinal angiogenesis imaging |
Arteriosclerosis, thrombosis, and vascular biology |
High |
26069237
|
| 2017 |
Plk1 phosphorylates Numb, leading to enhanced proteasomal degradation of Numb and impaired Numb/p53 pathway. Cells carrying the unphosphorylated form of Numb are more sensitive to doxorubicin. This identifies a mechanism by which Plk1 antagonizes p53 during DNA damage response via Numb destabilization. |
In vitro Plk1 kinase assay, proteasome inhibitor experiments, phosphomimetic/unphosphorylatable Numb mutants, doxorubicin sensitivity assay, xenograft mouse model |
Oncogene |
High |
29059161
|
| 2018 |
NUMB binds directly to the ARF6 guanine nucleotide exchange factor EFA6B through its PTB domain (recognizing an N-terminal NPLF motif) and promotes EFA6B exchange activity in vitro. A NUMB-EFA6B-ARF6 axis regulates recycling of RAC1 and is critical for formation of circular dorsal ruffles and acquisition of mesenchymal migration. Loss of NUMB promotes HGF-induced cell migration and invasion. |
Co-immunoprecipitation, in vitro GEF activity assay, PTB domain mutant analysis, RNAi knockdown, cell migration/invasion assay |
The Journal of cell biology |
High |
30061108
|
| 2020 |
NUMB stabilizes the NOTCH1 intracellular domain (N1ICD) by recruiting the deubiquitinase BAP1 to N1ICD, facilitating the BAP1-BRCA1 complex interaction with N1ICD to reduce its ubiquitination. This stabilization is independent of NUMB's role in endocytosis. BAP1 stabilizes N1ICD independent of its DUB catalytic activity but relying on its BRCA1-inhibiting function. |
Co-immunoprecipitation, ubiquitination assay, BAP1 catalytic mutant analysis, N1ICD stability assay, cortical neural progenitor cell assay |
Journal of molecular cell biology |
Medium |
31504682
|
| 2023 |
Numb binds Parkin and facilitates Parkin-mediated mitophagy (mitochondrial quality control). Deficiency in the Numb/Parkin pathway in prostate or lung adenocarcinomas causes metabolic reprogramming with increased lactate production, upregulation of histone lactylation, and transcription of neuroendocrine-associated genes driving cell fate transition. |
Co-immunoprecipitation (Numb-Parkin binding), mitophagy assay, Numb KO cell lines, metabolomics, histone lactylation measurement |
Cell reports |
Medium |
36724072
|
| 2024 |
Numb localizes to the ciliary pocket and acts as an endocytic adaptor to incorporate Ptch1 into clathrin-coated vesicles, promoting Ptch1 exit from the cilium. Loss of Numb impedes Shh-induced Ptch1 exit from the cilium, reduces Hedgehog signaling, impairs Shh-induced neural progenitor differentiation, and reduces cerebellar granule cell precursor proliferation in vivo. |
Proximity labeling and quantitative proteomics (ciliary Numb identification), live imaging of Ptch1 ciliary exit, Numb conditional KO in cerebellum, neural progenitor differentiation assays |
Nature communications |
High |
38664376
|
| 2023 |
High cell density induces phosphorylation of SPTAN1 (spectrin alpha), which recruits NUMB isoforms 1 and 2 (long PTB-containing isoforms) to the plasma membrane. NUMB then sequesters MARK kinases at the membrane, rendering them inaccessible for phosphorylation and inhibition of Hippo kinases MST1/2, thereby activating Hippo signaling and blocking YAP activity for cell contact inhibition. Low cell density leads to SPTAN1 dephosphorylation and NUMB cytoplasmic relocation, releasing MARKs to inhibit MST1/2 and activate YAP. |
Co-immunoprecipitation (NUMB-SPTAN1, NUMB-MARK), NUMB isoform-specific KO, liver-specific double KO (NUMB/WW45), phospho-SPTAN1 assays, Hippo kinase activity assay |
The Journal of clinical investigation |
High |
37843276
|
| 2003 |
A novel transmembrane protein NIP (Numb-interacting protein) contains NXXF motifs that bind the PTB domain of Numb. Expression of NIP in COS-7 cells recruits Numb from cytosol to plasma membrane in a NXXF-dependent manner. RNAi knockdown of NIP in Drosophila S2 cells releases Numb to the cytosol. In dividing Drosophila neuroblasts, NIP colocalizes with Numb in a basal cortical crescent. |
Co-immunoprecipitation, RNAi knockdown, membrane recruitment assay, immunofluorescence in Drosophila neuroblasts |
The Journal of biological chemistry |
Medium |
14670962
|
| 2006 |
LNX1 (Ligand-of-Numb protein X1) provides an endocytic scaffold for JAM4; LNX1 facilitates endocytosis of JAM4, and Numb is necessary for LNX1-mediated JAM4 endocytosis. JAM4, LNX1, and Numb form a tripartite complex in vitro. LNX1 is involved in TGF-beta-induced redistribution of JAM4. |
Yeast two-hybrid, co-immunoprecipitation from kidney lysates, in vitro tripartite complex reconstitution, dominant-negative and RNAi experiments, endocytosis assay |
Oncogene |
Medium |
16832352
|
| 2016 |
Numb directly interacts with VEGFR2 and VEGFR3 and controls their endocytosis and recycling. Numb proteins counteract VEGF receptor degradation and promote VEGFR2 recycling to the plasma membrane, sustaining VEGF receptor activation in response to ligand. |
Co-immunoprecipitation, receptor recycling/degradation assay, Numb/Numbl inducible endothelial KO, VEGF signaling assays |
Arteriosclerosis, thrombosis, and vascular biology |
High |
26069237
|
| 1999 |
Genetic epistasis in Drosophila CNS shows that both Notch and Numb function downstream of cell division genes (cyclinA, rca1, string/cdc25). In the absence of cell cycle entry into metaphase, Numb protein prevents Notch signaling from specifying sib fate; progression through the cell cycle is required for asymmetric localization of Numb. |
Genetic epistasis using loss-of-function mutations in cyclinA, rca1, stg, numb, Notch; double-mutant analysis; nocodazole treatment |
Development (Cambridge, England) |
High |
10331986
|
| 2022 |
Numb regulates intracellular Tau levels; conditional inactivation of Numb in retinal ganglion cells increases Tau levels and leads to axonal blebbing and neuronal loss. In the TauP301S tauopathy model, conditional Numb inactivation accelerates neurodegeneration. Overexpression of the long Numb isoform (Numb-72) decreases intracellular Tau levels and reduces axonal blebbing. |
Conditional KO of Numb in RGCs and spinal motoneurons, TauP301S cross, Tau level quantification by western blot, axonal blebbing assay, behavioral test, electrophysiology of cultured neurons |
Science advances |
High |
36260685
|
| 2016 |
The splicing factors ASF/SF2 and PTBP1 regulate alternative splicing of Numb exon 9 (E9). Activation of the MAPK/ERK pathway promotes E9 inclusion (producing p72/p71 isoforms) in cancer cells, switching Numb isoform expression from E9-excluded (differentiated cell) to E9-included (progenitor) forms. |
Splicing reporter assay, siRNA knockdown of splicing factors, MEK/ERK inhibitor and activator treatment, RT-PCR isoform analysis |
Oncogene |
Medium |
27041567
|
| 2015 |
Numb is required for preventing p53-dependent senescence in skeletal muscle stem cells following injury. In Numb-deficient satellite cells, senescence is rescued to wild-type levels by antioxidant treatment or p53 ablation, establishing that Numb acts upstream of p53 to prevent oxidative stress-induced senescence. |
Conditional Numb KO in muscle satellite cells, antioxidant treatment rescue, p53 genetic ablation rescue, senescence assay |
Nature communications |
High |
26503169
|
| 2010 |
Numb depletion in MDCK cells destabilizes E-cadherin-based cell-cell adhesion and promotes loss of epithelial cell morphology. Numb knockdown potentiates HGF-induced lamellipodia formation and cell dispersal via hyperactivation of Rac1-GTP. Rac1 inhibition in Numb-depleted cells stabilizes cell-cell contacts, establishing that Numb acts to suppress Rac1-GTP accumulation. |
shRNA knockdown, Rac1-GTP pull-down assay, Rac1 inhibitor rescue, HGF-stimulated cell scattering assay |
Experimental cell research |
Medium |
21147098
|