Gene Ontology annotation through association of InterPro records with GO terms.
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt.
Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara.
Combined Automated Annotation using Multiple IEA Methods.
NPHS2, encoding the glomerular protein podocin, is mutated in autosomal recessive steroid-resistant nephrotic syndrome.
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Identified NPHS2 gene on chromosome 1q25-31 encoding podocin, a stomatin family integral membrane protein
"NPHS2 is almost exclusively expressed in the podocytes of fetal and mature kidney glomeruli, and encodes a new integral membrane protein, podocin, belonging to the stomatin protein family."
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NPHS2 almost exclusively expressed in podocytes of fetal and mature kidney glomeruli
"NPHS2 is almost exclusively expressed in the podocytes of fetal and mature kidney glomeruli, and encodes a new integral membrane protein, podocin, belonging to the stomatin protein family"
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Ten different mutations found segregating with disease, demonstrating crucial role in glomerular filtration
"We found ten different NPHS2 mutations, comprising nonsense, frameshift and missense mutations, to segregate with the disease, demonstrating a crucial role for podocin in the function of the glomerular filtration barrier."
Podocin localizes in the kidney to the slit diaphragm area.
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NPHS2 first expressed in mesonephric podocytes from S-shaped body stage
"In metanephric kidneys, the NPHS2 transcript was initially detected in the lower limb of the late S-shaped body, in the presumptive podocytes but not in future parietal epithelial cells"
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Immunogold EM precisely localized podocin to cytoplasmic face of slit diaphragm
"23 Using immunogold labeling and electron microsopy, we showed the podocin distribution at the base of the foot processes and precisely determined its localization on either side of the slit diaphragm, the slit membrane itself being unlabeled"
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Both N- and C-termini face cytoplasm, confirming hairpin membrane topology
"Interestingly, both the C- and N-terminal domains of the protein identified by specific antibodies are co-localized at the cytoplasmic face of the plasma membrane, a finding in agreement with the hairpin-like predicted structure of podocin"
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Podocin may serve to anchor slit diaphragm components to cytoskeleton
"Our results suggest that podocin could serve to anchor directly or indirectly components of the slit diaphragm to the cytoskeleton."
NEPH1 defines a novel family of podocin interacting proteins.
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NEPH1 family proteins interact with C-terminal domain of podocin
"We report now that NEPH1 belongs to a family of three closely related proteins that interact with the C-terminal domain of podocin"
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Conserved podocin-binding motif in all three NEPH proteins
"All three NEPH proteins share a conserved podocin-binding motif; mutation of a centrally located tyrosine residue dramatically lowers the affinity of NEPH1 for podocin"
Podocin participates in the assembly of tight junctions between foot processes in nephrotic podocytes.
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Podocin colocalizes with CAR and ZO-1 at tight junctions in nephrotic podocytes
"In this study, we confirmed that podocin colocalizes with CAR and ZO-1 at the tight junction between foot processes in nephrotic rats"
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Podocin recruited to cell-cell contact sites
"Using primary cultures of rat podocytes, as well as cell lines that co-expressed podocin and CAR, we observed that podocin was recruited to sites of cell-cell contact and that it co-localized with CAR and ZO-1"
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Podocin facilitates coalescence of lipid rafts and restricts their lateral mobility
"Consistent with this, we found that podociin facilitated the coalescence of preassembled lipid rafts containing CAR and restricted their lateral mobility, the latter likely a result of dynamic actin reorganization and subsequent tethering of CAR-podocin complexes to the cytoskeleton"
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Podocin serves as scaffold linking junction proteins to actin cytoskeleton
"our data suggest that podocin may also serve as a scaffold that links tight junction proteins to the actin cytoskeleton in nephrotic foot processes"
Large-scale proteomics and phosphoproteomics of urinary exosomes.
IQGAP1 interacts with components of the slit diaphragm complex in podocytes and is involved in podocyte migration and permeability in vitro.
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IQGAP1 interacts with podocin in podocytes via immunoprecipitation
"Interactions between IQGAP1 and podocin or NCK1/2 were detected in podocytes (Figure 3D and 3E)"
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In situ Proximity Ligation assay confirmed IQGAP1-podocin interaction
"The In situ Proximity Ligation assay confirmed interactions between IQGAP1 and proteins of the slit diaphragm complex, nephrin, MAGI-1, CD2AP, podocin and NCK1/2"
In-depth proteomic analyses of exosomes isolated from expressed prostatic secretions in urine.
Nephrin interacts with Podocin
Deep research on NPHS2 function
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Podocin is a 383 amino acid protein with hairpin membrane topology
"The hairpin structure positions both the N-terminal region (amino acids 1-100) and the C-terminal region (amino acids 126-383) intracellularly within the cytoplasm."
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PHB domain binds cholesterol for lipid raft organization
"Biochemical studies have demonstrated direct binding of cholesterol to podocin through residues in the PHB domain."
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Forms high-order oligomers in 1.5-3 MDa complexes
"Podocin is present in native slit diaphragms as part of macromolecular assemblies with apparent molecular weights in the range of 1.5-3 megadaltons."
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Regulates TRPC6 mechanosensitive channel activity
"Podocin lacking the PHB domain (PodocinDeltaPHB) fails to bind cholesterol and does not properly activate TRPC6."
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Mutations cause autosomal recessive SRNS with FSGS
"Mutations in NPHS2 cause autosomal recessive steroid-resistant nephrotic syndrome."
Falcon deep research on NPHS2/podocin function
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Podocin's primary molecular role is membrane microdomain organizer/scaffold; not an enzyme or classical transporter
"Podocin is not an enzyme catalyzing a chemical reaction, nor a classical transporter. Instead, convergent evidence supports podocin's primary molecular role as a membrane microdomain organizer/scaffold"
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Podocin partitions into detergent-resistant membrane fractions consistent with lipid raft association
"Primary and mechanistic studies localize podocin to the podocyte slit diaphragm and show it partitions into detergent-resistant membrane (DRM) fractions, consistent with lipid raft association"
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Podocin recruits nephrin into lipid raft microdomains required for nephrin signaling at the slit diaphragm
"podocin recruits nephrin into lipid raft microdomains at the slit diaphragm, which is necessary for nephrin-dependent signal transduction"
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Wild-type podocin augments TRPC6 currents; topology-disrupting mutants fail to do so
"wild-type podocin augments TRPC6 currents, whereas topology-disrupting mutants fail to do so"
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Podocin forms megadalton supercomplexes via the PHB domain; site-specific ubiquitylation (K301) regulates stability
"podocin forms large megadalton complexes mediated by the PHB domain and identify site-specific ubiquitylation (e.g., K301) as affecting stability/unfolding"
Molecular basis of the functional podocin-nephrin complex: mutations in the NPHS2 gene disrupt nephrin targeting to lipid raft microdomains.
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Wild-type podocin is targeted to plasma membrane and forms homo-oligomers via C- and N-terminal cytoplasmic domains
"We show that wild-type podocin is targeted to the plasma membrane, and forms homo-oligomers involving the carboxy and amino terminal cytoplasmic domains."
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Association with lipid raft microdomains is required for podocin to recruit nephrin into rafts
"The association of podocin with specialized lipid raft microdomains of the plasma membrane was a prerequisite for recruitment of nephrin into rafts."
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R138Q mutant is retained in ER; R138X reaches plasma membrane but fails to associate with rafts
"disease-causing mutations of podocin (R138Q and R138X) failed to recruit nephrin into rafts either because these mutants were retained in the endoplasmic reticulum (R138Q), or because they failed to associate with rafts (R138X) despite their presence in the plasma membrane."
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Failure of mutant podocin to recruit nephrin into lipid rafts is essential for NPHS2 pathogenesis
"Our findings demonstrate that the failure of mutant podocin to recruit nephrin into lipid rafts may be essential for the pathogenesis of NPHS2."
A disease-causing mutation illuminates the protein membrane topology of the kidney-expressed prohibitin homology (PHB) domain protein podocin.
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Podocin is a key component of the slit diaphragm and part of a multiprotein-lipid supercomplex
"The NPHS2 gene product podocin is a key component of the slit diaphragm cell junction at the kidney filtration barrier and part of a multiprotein-lipid supercomplex."
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Hairpin-like topology with both N- and C-termini facing the cytoplasm
"podocin and MEC-2 are membrane-associated proteins with a predicted hairpin-like structure and amino and carboxyl termini facing the cytoplasm"
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P118L mutant C-terminus projects extracellularly and becomes N-glycosylated; loses DRM fractionation
"we show that both mutant proteins, in contrast to the wild-type variants, are N-glycosylated because of the fact that the mutant C termini project extracellularly. Podocin(P118L) and MEC-2(P134S) did not fractionate in detergent-resistant membrane domains."
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Correct cytoplasmic C-terminus topology is required for cholesterol binding and TRPC6 activation
"the carboxyl terminus of podocin/MEC-2 has to be placed at the inner leaflet of the plasma membrane to mediate cholesterol binding and contribute to ion channel activity, a prerequisite for mechanosensation and the integrity of the kidney filtration barrier."
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Mutant podocin fails to activate TRPC6
"mutant podocin failed to activate the ion channel TRPC6, which is part of the multiprotein-lipid supercomplex"
The ubiquitin ligase Ubr4 controls stability of podocin/MEC-2 supercomplexes.
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Podocin and MEC-2 are key components of mechanosensitive membrane protein signaling complexes
"Podocin and its Caenorhabditis elegans orthologue MEC-2 have emerged as key components of mechanosensitive membrane protein signalling complexes."
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Ubr4 ubiquitin ligase colocalizes with podocin and regulates its stability
"the ubiquitin ligase Ubr4 is a key component of the podocin interactome purified both from cultured podocytes and native glomeruli. It colocalizes with podocin and regulates its stability."
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Podocin is ubiquitylated at two conserved lysine residues in an Ubr4-dependent manner
"Ubiquitylomic analysis of mouse glomeruli revealed that podocin is ubiquitylated at two lysine residues. These sites were Ubr4-dependent and were conserved across species."
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K301 ubiquitylation may also affect stability and disassembly of the multimeric complex
"ubiquitylation of one site, K301, do not only target podocin/MEC-2 for proteasomal degradation, but may also affect stability and disassembly of the multimeric complex."
In vivo characterization of a podocyte-expressed short podocin isoform.
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Podocin is a cholesterol-binding, lipid-raft associated protein
"mutations in the NPHS2 gene, which encodes the cholesterol-binding, lipid-raft associated protein podocin"
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Short (Δexon5) isoform is mostly retained in the endoplasmic reticulum
"Experiments in cell culture could show that this isoform is mostly retained in the endoplasmic reticulum, which is a pathogenic feature known from other disease causing mutations of podocin"
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Homozygous podocinΔexon5 mice show severe congenital albuminuria and neonatal lethality
"Mice homozygous for podocinΔexon5 were born heavily albuminuric and did not survive past the first 24 h after birth."
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STED microscopy shows complete absence of podocin at the slit diaphragm in homozygous Δexon5 mice
"STED microscopy revealed the complete absence of podocin at the podocytes' slit diaphragm and severe morphological alterations of podocyte foot processes."
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Reduction of podocin at the slit diaphragm is associated with decreased nephrin protein abundance
"Reduction of podocin levels at the site of the slit diaphragm complex has a detrimental effect on podocyte function and morphology. It is associated with decreased protein abundance of nephrin, the central component of the filtration-slit forming slit diaphragm protein complex."