| 1998 |
LNX1 was identified as a novel protein that interacts specifically with the Numb PTB domain via the sequence motif LDNPAY. Mutational analysis and peptide competition experiments showed that tyrosine phosphorylation within this motif was not required for Numb PTB domain binding. Phosphorylation of tyrosine in LDNPAY could generate a binding site for other PTB domain-containing proteins such as SHC. |
Yeast two-hybrid screen, mutational analysis, peptide competition experiments |
The Journal of biological chemistry |
Medium |
9535908
|
| 2002 |
LNX1 functions as a RING-type E3 ubiquitin ligase; its isolated RING finger domain has E2-dependent ubiquitin ligase activity in vitro, and mutation of a conserved cysteine residue within the RING domain abolishes this activity. Numb is a substrate of LNX1 E3 activity both in vitro and in vivo. A region including the Numb PTB domain-binding site and the first PDZ domain is required for Numb ubiquitylation. Expression of wild-type but not mutant LNX causes proteasome-dependent degradation of Numb and can enhance Notch signalling. |
In vitro ubiquitin ligase assay, active-site mutagenesis (RING domain cysteine mutation), in vivo ubiquitination assay, proteasome inhibitor experiments |
The EMBO journal |
High |
11782429
|
| 2001 |
LNX1 and LNX2 form oligomers via their PDZ domains binding to PDZ-binding consensus motifs located in their C-termini, or by homophilic oligomerization of their RING fingers. LNX proteins bind Numb and Numblike via their NPXY motifs, and oligomerization and Numb binding occur simultaneously, suggesting LNX proteins serve as molecular scaffolds. |
Protein interaction assays, yeast two-hybrid, molecular biology |
Molecular and cellular neurosciences |
Medium |
11922143
|
| 2002 |
LNX1 interacts with the intracellular tail of the Coxsackievirus and adenovirus receptor (CAR) both in vivo and in vitro. Efficient binding required not only the consensus PDZ domain-binding motif in the C-terminus of CAR but also upstream sequences. The CAR binding region in LNX1 was mapped to the second PDZ domain. CAR and LNX1 colocalize in mammalian cells. |
Yeast two-hybrid screen, in vivo and in vitro binding assays, colocalization by immunostaining |
The Journal of biological chemistry |
Medium |
12468544
|
| 2005 |
LNX1 directly interacts with the ErbB2 receptor and is specifically localized in perisynaptic Schwann cells at the neuromuscular junction but not in Schwann cells along the motor axon. LNX1 protein levels are inversely correlated with the responsiveness of perisynaptic Schwann cells to neuregulin-1, and LNX1 staining disappears upon denervation while ErbB2 reappears. |
Co-immunoprecipitation, immunostaining/localization, denervation experiments |
Molecular and cellular neurosciences |
Medium |
16122940
|
| 2005 |
Human LNX1 interacts with SKIP (Ski interacting protein) via its PDZ domains. This interaction was confirmed by co-immunoprecipitation in HEK293 cells. LNX1 can affect the subcellular localization of Numb, suggesting LNX1 functions as a molecular anchor that localizes Numb to the subcellular site of its interaction with Notch. |
Yeast two-hybrid, co-immunoprecipitation, subcellular localization assay |
The international journal of biochemistry & cell biology |
Low |
16002321
|
| 2009 |
LNX1 (Lnx-like/Lnx-2b in zebrafish) was identified as a critical E3 ubiquitin ligase that binds Bozozok (Boz) and induces K48-linked polyubiquitylation of Boz leading to its proteasomal degradation, thereby restricting dorso-ventral axis formation. Dorsalization by Boz overexpression was suppressed by raising Lnx-l levels but not when Boz lacked the critical Lnx-l binding motif. |
Morpholino knockdown in zebrafish, K48-linked ubiquitination assay in 293T cells and zebrafish, genetic epistasis (double morpholino/overexpression), binding assays |
Nature cell biology |
High |
19668196
|
| 2009 |
LNX1 interacts with RhoC (a Ras family small GTPase) via its first PDZ domain, as shown by yeast two-hybrid and co-immunoprecipitation in mammalian cells. Co-expression of LNX1 causes RhoC to change its sublocalization from cytoplasm to nucleus. Co-expression of RhoC reduced the transcriptional activity of AP-1, which was upregulated by LNX1 overexpression alone. |
Yeast two-hybrid, co-immunoprecipitation, subcellular localization assay, AP-1 reporter assay |
Molecular biology reports |
Low |
19701800
|
| 2011 |
LNX1 PDZ domains are phylogenetically related to PDZ domains in MUPP1 and share common binding specificities with MUPP1 ligands. Novel LNX1 interactions with three known MUPP1 ligands were identified by yeast two-hybrid assays, supporting functional conservation between LNX and MUPP1 PDZ domains. |
Yeast two-hybrid assays, phylogenetic analysis |
BMC evolutionary biology |
Low |
21827680
|
| 2011 |
A human protein array screen identified 53 potential direct LNX1 PDZ domain binding partners from 8,000 human proteins. Six novel LNX1 binding partners were confirmed: KCNA4, PAK6, PLEKHG5, PKC-alpha1, TYK2, and PBK. These interactions suggest LNX1 functions as a signalling scaffold. |
Human protein array, co-immunoprecipitation validation |
PloS one |
Medium |
22087225
|
| 2012 |
LNX1 ubiquitinates substrates via its PDZ domains binding to C-termini of target proteins. PDZ-binding kinase (PBK) and BCR were identified and confirmed as novel endogenous LNX1 substrates in vivo. LNX1-mediated ubiquitination and degradation of PBK inhibited cell proliferation and enhanced sensitivity to doxorubicin-induced apoptosis. |
Yeast two-hybrid peptide library screen, in vitro ubiquitination assay, in vivo substrate validation, cell proliferation and apoptosis assays |
Journal of proteome research |
Medium |
22889411
|
| 2014 |
The 5' untranslated region of the Lnx1_variant 2 mRNA (generating LNX1p70 isoform) strongly suppresses protein production, mediated in part by upstream open reading frames (uORFs) and a sequence element that decreases mRNA levels and translational efficiency. By contrast, protein turnover via proteasomal degradation influences LNX1p80 levels. |
Luciferase reporter assays, uORF mutational analysis |
Gene |
Medium |
25200495
|
| 2017 |
LNX1 ubiquitinates PPFIA1 (liprin-α1), KLHL11, KIF7, and ERC2 as substrates. LNX1 ubiquitination of liprin-α1 is dependent on a PDZ-binding motif containing a carboxyl-terminal cysteine that binds LNX1 PDZ2. The neuronal LNX1p70 isoform (lacking the RING domain) can also promote ubiquitination of PPFIA1 and KLHL11, possibly by acting as a scaffold recruiting other E3 ligases. LNX1 interacts with MID2/TRIM1 and TRIM27. |
Affinity purification/mass spectrometry, in vitro ubiquitination assays, co-immunoprecipitation, mutational analysis of PDZ-binding motif |
PloS one |
Medium |
29121065
|
| 2018 |
The crystal structure of the LNX1 ubiquitination domain in complex with Ubc13~Ubiquitin was determined. The RING domain of LNX1 is embedded between two zinc-finger motifs (Zn-RING-Zn), both required for ubiquitination activity. In the heterodimeric complex, ubiquitin from one monomer shares more buried surface area with LNX1 of the other monomer, and these interactions are essential for catalysis. Ubc13/Ube2V2 was identified as a functional E2 for LNX1 in vitro. |
Crystal structure determination, in vitro ubiquitination assay, mutagenesis |
Journal of molecular biology |
High |
29496391
|
| 2018 |
LNX1 and LNX2 directly interact with connexin36 (Cx36), the key component of gap junctions forming electrical synapses in the mammalian CNS. Interaction was demonstrated by coimmunoprecipitation and pull-down with the second PDZ domain of LNX1/LNX2. Cotransfection of cells with Cx36 and E3 ligase-competent LNX1/LNX2 isoforms led to loss of Cx36-containing gap junctions, whereas isoforms lacking ligase activity did not cause this loss, suggesting LNX mediates ubiquitination of Cx36 with consequent Cx36 internalization. |
Immunofluorescence colocalization, co-immunoprecipitation, pull-down with isolated PDZ domains, cotransfection with ligase-competent vs. ligase-dead isoforms |
The European journal of neuroscience |
Medium |
30295974
|
| 2018 |
Postsynaptic Lnx1 in hippocampal CA3 pyramidal neurons is essential for mossy fiber axon targeting and terminal maturation. Lnx1 deletion causes defective synaptic arrangement and aberrant presynaptic terminals. EphB1 and EphB2 receptors were identified as novel Lnx1-binding proteins forming a multiprotein complex stabilized on the CA3 neuron membrane by prevention of proteasome activity. Constitutively active EphB2 kinase rescues MF terminal structure in Lnx1 mutant mice. |
Lnx1 knockout mice, synaptic morphology analysis, co-immunoprecipitation of EphB-Lnx1 complex, proteasome inhibitor experiments, constitutively active EphB2 rescue |
The Journal of cell biology |
High |
30185604
|
| 2019 |
LNX1 and LNX2 ubiquitinate the presynaptic glycine transporter GlyT2. The N-terminal RING-finger domain of LNX1/2 ubiquitinates a cytoplasmic C-terminal lysine cluster in GlyT2 (K751, K773, K787, K791), regulating GlyT2 expression levels and transport activity. Genetic deletion of endogenous LNX2 in spinal cord primary neurons increases GlyT2 expression, and LNX2 is required for PKC-mediated control of GlyT2 transport. |
Unbiased screening, in vitro ubiquitination assays (RING domain), site-directed mutagenesis of lysine residues, LNX2 genetic knockout in neurons, transport activity assays |
Scientific reports |
High |
31628376
|
| 2019 |
LDOC1 forms a multiprotein complex with phospho-JAK2 (pJAK2) and LNX1, targeting pJAK2 for ubiquitin-dependent proteasomal degradation. LDOC1 deficiency attenuates the interactions between LNX1 and pJAK2, leading to ineffective ubiquitination of pJAK2 and consequent activation of STAT3. |
Co-immunoprecipitation, immunofluorescent confocal microscopy, ubiquitination assay, knockdown/overexpression functional studies |
Cancers |
Medium |
30634502
|
| 2019 |
Hippocampal CA3 Lnx1 is required for initial social memory and partner discrimination in juvenile mice. Lnx1 deletion causes NMDAR hypofunction attributable to decreased GluN2B expression in the PSD compartment and disruption of the Lnx1-NMDAR-EphB2 complex. Specific restoration of Lnx1 or EphB2 in CA3 of Lnx1-/- mice rescues defective synaptic function and social memory. |
Gene targeting (knockout mice), electrophysiology (NMDAR function), PSD fractionation and Western blotting, co-immunoprecipitation of Lnx1-NMDAR-EphB2 complex, stereotaxic viral rescue |
Molecular psychiatry |
High |
31772302
|
| 2019 |
LNX1 interacts with p53 and MDM2, and increases ubiquitination of p53 in an MDM2-dependent manner, thereby decreasing p53 half-life and inhibiting p53-dependent transcription. LNX1 KO (by CRISPR) in p53 wild-type cancer cells increased p53 stability and p53-dependent transcription, and impaired tumor growth in vivo. |
Co-immunoprecipitation, CRISPR-Cas9 KO, ubiquitination assay, p53 half-life assay, tumor xenograft model |
FASEB journal |
Medium |
31533005
|
| 2020 |
miR-325-3p directly targets LNX1 (as an E3 ubiquitin ligase of NEK6), and its upregulation after M. tuberculosis infection reduces LNX1 levels, hampers proteasomal degradation of NEK6, and leads to NEK6 accumulation. Abnormal NEK6 accumulation activates STAT3 signaling, inhibiting apoptosis and promoting intracellular M. tuberculosis survival. |
miR-325-3p target validation, LNX1 knockdown/overexpression, Mir325 knockout mice, NEK6 ubiquitination assay, STAT3 signaling readouts |
mBio |
Medium |
32487755
|
| 2020 |
LNX1 is strongly upregulated after temozolomide therapy in glioblastoma and promotes Notch1 signaling by targeting negative regulator Numb for degradation. Overexpression of LNX1 results in Notch1 signaling activation and increased glioma stem cell populations; LNX1 knockdown reverses these changes and results in more prolonged survival in a mouse model. |
Gene set expression analysis, LNX1 overexpression/knockdown in patient-derived xenograft cells, Western blotting for Numb/NICD, mouse survival model |
Cancers |
Medium |
33255632
|
| 2022 |
LNX1 mediates non-degrading ubiquitination (NDU) of RhoC (but not RhoA), activating RhoC. This ubiquitination is negatively regulated by LIS1 (PAFAH1B1): LIS1 inhibits LNX1's effects on the RhoGDI-RhoC interaction, providing a molecular mechanism for LIS1-dependent regulation of Rho GTPase activity. |
In vitro ubiquitination assay distinguishing RhoC vs RhoA, RhoGDI-RhoC interaction assay, LIS1 inhibition experiments |
Scientific reports |
Medium |
36192543
|
| 2022 |
Lnx1 stabilizes EphB receptors (EphB1, EphB2) at the postsynaptic membrane; loss of Lnx1 promotes internalization of EphB receptors from the cell surface, leading to abnormal dendritic spine development and impaired synaptogenesis. Constitutively active EphB2 intracellular signaling rescues synaptogenesis in Lnx1 mutant mice. |
Lnx1 knockout mice, EphB receptor internalization assay, dendritic spine morphology analysis, constitutively active EphB2 rescue |
Frontiers in molecular neuroscience |
Medium |
35531068
|