The Experts below are selected from a list of 3321 Experts worldwide ranked by ideXlab platform
Tobias B. Huber - One of the best experts on this subject based on the ideXlab platform.
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A novel domain regulating degradation of the glomerular slit diaphragm protein Podocin in cell culture systems.
PloS one, 2013Co-Authors: Markus Gödel, Benjamin N. Ostendorf, Jessica Baumer, Katrin L. Weber, Tobias B. HuberAbstract:Mutations in the gene NPHS2 are the most common cause of hereditary steroid-resistant nephrotic syndrome. Its gene product, the stomatin family member protein Podocin represents a core component of the slit diaphragm, a unique structure that bridges the space between adjacent podocyte foot processes in the kidney glomerulus. Dislocation and misexpression of slit diaphragm components have been described in the pathogenesis of acquired and hereditary nephrotic syndrome. However, little is known about mechanisms regulating cellular trafficking and turnover of Podocin. Here, we discover a three amino acids-comprising motif regulating intracellular localization of Podocin in cell culture systems. Mutations of this motif led to markedly reduced degradation of Podocin. These findings give novel insight into the molecular biology of the slit diaphragm protein Podocin, enabling future research to establish the biological relevance of Podocin turnover and localization.
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Podocin and MEC-2 bind cholesterol to regulate the activity of associated ion channels.
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Tobias B. Huber, Bernhard Schermer, Martin Höhne, Malte P. Bartram, Roman-ulrich Müller, Andrea Calixto, Henning Hagmann, Christian Reinhardt, Fabienne Koos, Karl KunzelmannAbstract:The prohibitin (PHB)-domain proteins are membrane proteins that regulate a variety of biological activities, including mechanosensation, osmotic homeostasis, and cell signaling, although the mechanism of this regulation is unknown. We have studied two members of this large protein family, MEC-2, which is needed for touch sensitivity in Caenorhabditis elegans, and Podocin, a protein involved in the function of the filtration barrier in the mammalian kidney, and find that both proteins bind cholesterol. This binding requires the PHB domain (including palmitoylation sites within it) and part of the N-terminally adjacent hydrophobic domain that attaches the proteins to the inner leaflet of the plasma membrane. By binding to MEC-2 and Podocin, cholesterol associates with ion-channel complexes to which these proteins bind: DEG/ENaC channels for MEC-2 and TRPC channels for Podocin. Both the MEC-2-dependent activation of mechanosensation and the Podocin-dependent activation of TRPC channels require cholesterol. Thus, MEC-2, Podocin, and probably many other PHB-domain proteins by binding to themselves, cholesterol, and target proteins regulate the formation and function of large protein–cholesterol supercomplexes in the plasma membrane.
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molecular basis of the functional Podocin nephrin complex mutations in the nphs2 gene disrupt nephrin targeting to lipid raft microdomains
Human Molecular Genetics, 2003Co-Authors: Tobias B. Huber, Miriam Schmidts, Moin A. Saleem, Gerd Walz, Matias Simons, Björn Hartleben, Leonie Sernetz, Enken Gundlach, Thomas BenzingAbstract:Hereditary nephrotic syndrome is a heterogeneous disease, characterized by heavy proteinuria and renal failure. Mutations of NPHS1 or NPHS2, the genes encoding for nephrin and Podocin, lead to early onset of heavy proteinuria, and rapid progression to end-stage renal disease, suggesting that both proteins are essential for the integrity of the glomerular filter. Podocin is a stomatin protein family member with a predicted hairpin-like structure localizing to the insertion site of the slit diaphragm of podocytes, the visceral glomerular epithelial cells of the kidney. Here we investigate the pathomechanisms of different disease-causing Podocin mutations. We show that wild-type Podocin is targeted to the plasma membrane, and forms homo-oligomers involving the carboxy and amino terminal cytoplasmic domains. The association of Podocin with specialized lipid raft microdomains of the plasma membrane was a prerequisite for recruitment of nephrin into rafts. In contrast, 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. None of the mutants did augment nephrin signaling, suggesting that lipid raft targeting facilitates nephrin signaling. Our findings demonstrate that the failure of mutant Podocin to recruit nephrin into lipid rafts may be essential for the pathogenesis of NPHS2.
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Molecular basis of the functional Podocin–nephrin complex: mutations in the NPHS2 gene disrupt nephrin targeting to lipid raft microdomains
Human molecular genetics, 2003Co-Authors: Tobias B. Huber, Miriam Schmidts, Moin A. Saleem, Gerd Walz, Matias Simons, Björn Hartleben, Leonie Sernetz, Enken Gundlach, Thomas BenzingAbstract:Hereditary nephrotic syndrome is a heterogeneous disease, characterized by heavy proteinuria and renal failure. Mutations of NPHS1 or NPHS2, the genes encoding for nephrin and Podocin, lead to early onset of heavy proteinuria, and rapid progression to end-stage renal disease, suggesting that both proteins are essential for the integrity of the glomerular filter. Podocin is a stomatin protein family member with a predicted hairpin-like structure localizing to the insertion site of the slit diaphragm of podocytes, the visceral glomerular epithelial cells of the kidney. Here we investigate the pathomechanisms of different disease-causing Podocin mutations. We show that wild-type Podocin is targeted to the plasma membrane, and forms homo-oligomers involving the carboxy and amino terminal cytoplasmic domains. The association of Podocin with specialized lipid raft microdomains of the plasma membrane was a prerequisite for recruitment of nephrin into rafts. In contrast, 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. None of the mutants did augment nephrin signaling, suggesting that lipid raft targeting facilitates nephrin signaling. Our findings demonstrate that the failure of mutant Podocin to recruit nephrin into lipid rafts may be essential for the pathogenesis of NPHS2.
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Interaction with Podocin Facilitates Nephrin Signaling
Journal of Biological Chemistry, 2001Co-Authors: Tobias B. Huber, Michael Köttgen, Gerd Walz, Birgit Schilling, Thomas BenzingAbstract:Abstract Mutations of NPHS1 orNPHS2, the genes encoding for the glomerular podocyte proteins nephrin and Podocin, cause steroid-resistant proteinuria. In addition, mice lacking CD2-associated protein (CD2AP) develop a nephrotic syndrome that resembles NPHS mutations suggesting that all three proteins are essential for the integrity of glomerular podocytes. Although the precise glomerular function of either protein remains unknown, it has been suggested that nephrin forms zipper-like interactions to maintain the structure of podocyte foot processes. We demonstrate now that nephrin is a signaling molecule, which stimulates mitogen-activated protein kinases. Nephrin-induced signaling is greatly enhanced by Podocin, which binds to the cytoplasmic tail of nephrin. Mutational analysis suggests that abnormal or inefficient signaling through the nephrin-Podocin complex contributes to the development of podocyte dysfunction and proteinuria.
Jinsheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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the relationship among nephrin Podocin cd2ap and α actinin might not be a true interaction in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1 , NPHS2 , CD2AP , and ACTN4 , can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or α -actinin-4 mRNA by using reconstructed RNA interference vector – psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of α -actinin-4, whereas α -actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
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the relationship among nephrin Podocin cd2ap and alpha actinin might not be a true interaction in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:: The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1, NPHS2, CD2AP, and ACTN4, can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or alpha-actinin-4 mRNA by using reconstructed RNA interference vector--psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of alpha-actinin-4, whereas alpha-actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
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the relationship among nephrin Podocin cd2ap and alpha actinin might not be a true lsquo interaction rsquo in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1, NPHS2, CD2AP, and ACTN4, can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or -actinin-4 mRNA by using reconstructed RNA interference vector – psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of -actinin-4, whereas -actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
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Original ArticleThe relationship among nephrin, Podocin, CD2AP, and α-actinin might not be a true ‘interaction’ in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1 , NPHS2 , CD2AP , and ACTN4 , can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or α -actinin-4 mRNA by using reconstructed RNA interference vector – psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of α -actinin-4, whereas α -actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
Markus M. Rinschen - One of the best experts on this subject based on the ideXlab platform.
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the ubiquitin ligase ubr4 controls stability of Podocin mec 2 supercomplexes
Human Molecular Genetics, 2016Co-Authors: Markus M. Rinschen, Puneet Bharill, Priyanka Kohli, Matthäus J. Reinert, Oliver Kretz, Isabel Saez, Bernhard Schermer, Martin Höhne, Malte P. Bartram, Sriram AravamudhanAbstract:The PHB-domain protein Podocin maintains the renal filtration barrier and its mutation is an important cause of hereditary nephrotic syndrome. Podocin and its Caenorhabditis elegans orthologue MEC-2 have emerged as key components of mechanosensitive membrane protein signalling complexes. Whereas Podocin resides at a specialized cell junction at the podocyte slit diaphragm, MEC-2 is found in neurons required for touch sensitivity. Here, we show that 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. In C. elegans, this process is conserved. Here, Ubr4 is responsible for the degradation of mislocalized MEC-2 multimers. Ubiquitylomic analysis of mouse glomeruli revealed that Podocin is ubiquitylated at two lysine residues. These sites were Ubr4-dependent and were conserved across species. Molecular dynamics simulations revealed that 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. We suggest that Ubr4 is a key regulator of podocyte foot process proteostasis.
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The ubiquitin ligase Ubr4 controls stability of Podocin/MEC-2 supercomplexes
Human molecular genetics, 2016Co-Authors: Markus M. Rinschen, Puneet Bharill, Priyanka Kohli, Matthäus J. Reinert, Oliver Kretz, Isabel Saez, Bernhard Schermer, Martin Höhne, Malte P. BartramAbstract:The PHB-domain protein Podocin maintains the renal filtration barrier and its mutation is an important cause of hereditary nephrotic syndrome. Podocin and its Caenorhabditis elegans orthologue MEC-2 have emerged as key components of mechanosensitive membrane protein signalling complexes. Whereas Podocin resides at a specialized cell junction at the podocyte slit diaphragm, MEC-2 is found in neurons required for touch sensitivity. Here, we show that 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. In C. elegans, this process is conserved. Here, Ubr4 is responsible for the degradation of mislocalized MEC-2 multimers. Ubiquitylomic analysis of mouse glomeruli revealed that Podocin is ubiquitylated at two lysine residues. These sites were Ubr4-dependent and were conserved across species. Molecular dynamics simulations revealed that 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. We suggest that Ubr4 is a key regulator of podocyte foot process proteostasis.
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a disease causing mutation illuminates the protein membrane topology of the kidney expressed prohibitin homology phb domain protein Podocin
Journal of Biological Chemistry, 2014Co-Authors: Eva-maria Schurek, Markus M. Rinschen, Linus A. Völker, Judit Tax, Tobias Lamkemeyer, Denise Ungrue, Karl Kunzelmann, John Ernest Kratz, Lalida Sirianant, Martin ChalfieAbstract:Mutations in the NPHS2 gene are a major cause of steroid-resistant nephrotic syndrome, a severe human kidney disorder. 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. A similar complex with the Podocin ortholog MEC-2 is required for touch sensation in Caenorhabditis elegans. Although Podocin and MEC-2 are membrane-associated proteins with a predicted hairpin-like structure and amino and carboxyl termini facing the cytoplasm, this membrane topology has not been convincingly confirmed. One particular mutation that causes kidney disease in humans (PodocinP118L) has also been identified in C. elegans in genetic screens for touch insensitivity (MEC-2P134S). Here 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. PodocinP118L and MEC-2P134S did not fractionate in detergent-resistant membrane domains. Moreover, mutant Podocin failed to activate the ion channel TRPC6, which is part of the multiprotein-lipid supercomplex, indicative of the fact that cholesterol recruitment to the ion channels, an intrinsic function of both proteins, requires C termini facing the cytoplasmic leaflet of the plasma membrane. Taken together, this study demonstrates that 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. Background: Mutations in the stomatin family protein Podocin are the most common genetic cause of proteinuria. Results: A conserved proline residue of Podocin is essential for its membrane topology. Conclusion: This study confirms a hairpin-like structure of the membrane-attached PHB domain protein and its significance for cholesterol recruitment. Significance: PodocinP118L elucidates the pathogenic implication in kidney disease and identifies a novel family of PHB domain proteins.
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a disease causing mutation illuminates the protein membrane topology of the kidney expressed prohibitin homology phb domain protein Podocin
Journal of Biological Chemistry, 2014Co-Authors: Eva-maria Schurek, Markus M. Rinschen, Linus A. Völker, Judit Tax, Tobias Lamkemeyer, Denise Ungrue, Karl Kunzelmann, John Ernest Kratz, Lalida Sirianant, Martin ChalfieAbstract:Mutations in the NPHS2 gene are a major cause of steroid-resistant nephrotic syndrome, a severe human kidney disorder. 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. A similar complex with the Podocin ortholog MEC-2 is required for touch sensation in Caenorhabditis elegans. Although Podocin and MEC-2 are membrane-associated proteins with a predicted hairpin-like structure and amino and carboxyl termini facing the cytoplasm, this membrane topology has not been convincingly confirmed. One particular mutation that causes kidney disease in humans (PodocinP118L) has also been identified in C. elegans in genetic screens for touch insensitivity (MEC-2P134S). Here 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. PodocinP118L and MEC-2P134S did not fractionate in detergent-resistant membrane domains. Moreover, mutant Podocin failed to activate the ion channel TRPC6, which is part of the multiprotein-lipid supercomplex, indicative of the fact that cholesterol recruitment to the ion channels, an intrinsic function of both proteins, requires C termini facing the cytoplasmic leaflet of the plasma membrane. Taken together, this study demonstrates that 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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Characterization of a short isoform of the kidney protein Podocin in human kidney
BMC nephrology, 2013Co-Authors: Linus A. Völker, Thomas Benzing, Markus M. Rinschen, Bernhard Schermer, Eva-maria Schurek, Judit Tax, Barbara A Schutte, Tobias Lamkemeyer, Denise Ungrue, Martin HöhneAbstract:Background Steroid resistant nephrotic syndrome is a severe hereditary disease often caused by mutations in the NPHS2 gene. This gene encodes the lipid binding protein Podocin which localizes to the slit diaphragm of podocytes and is essential for the maintenance of an intact glomerular filtration barrier. Podocin is a hairpin-like membrane-associated protein that multimerizes to recruit lipids of the plasma membrane. Recent evidence suggested that Podocin may exist in a canonical, well-studied large isoform and an ill-defined short isoform. Conclusive proof of the presence of this new Podocin protein in the human system is still lacking.
E Daphnis - One of the best experts on this subject based on the ideXlab platform.
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early treatment with glucocorticoids or cyclophosphamide retains the slit diaphragm proteins nephrin and Podocin in experimental lupus nephritis
Lupus, 2012Co-Authors: Dk Moysiadis, Gs Perysinaki, George Bertsias, Kyriacos Kyriacou, Lydia Nakopoulou, Dimitrios T. Boumpas, Stavros Stratakis, E DaphnisAbstract:Renal podocytes and their slit diaphragms ensure the integrity of renal basement membrane and prevent urinary protein loss. We have previously reported that decreases of the podocyte slit diaphragm proteins nephrin and Podocin represent early events in the podocytopathy of lupus nephritis (LN). We asked whether immunosuppressive agents such as glucocorticoids and cyclophosphamide may have direct effects on podocytes. We assessed in New Zealand Black/New Zealand White (NZB/W) F1 LN mice glomerular nephrin and Podocin expression and localization by the use of Western blot and immunofluorescence; mRNA levels were measured by real-time polymerase chain reaction (PCR) and renal histology by light and electron microscopy. Early treatment with glucocorticoids and cyclophosphamide halted the histologic alterations associated with LN, preserving podocyte foot processes. Nephrin and Podocin protein expression significantly increased in both glucocorticoid and cyclophosphamide groups as early as after three months of therapy. Real-time PCR revealed similar enhancement in nephrin and Podocin mRNA levels after three to six months of treatment. This study documents that early treatment in experimental LN with glucocorticoids or cyclophosphamide preserves slit diaphragm proteins in podocytes and halts histological changes of the glomeruli, thus raising the possibility of a direct protective effect of these drugs on podocytes.
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Podocyte main slit diaphragm proteins, nephrin and Podocin, are affected at early stages of lupus nephritis and correlate with disease histology.
Lupus, 2011Co-Authors: Gs Perysinaki, Dk Moysiadis, George Bertsias, I Giannopoulou, Kyriacos Kyriacou, Lydia Nakopoulou, Dimitrios T. Boumpas, E DaphnisAbstract:Renal podocytes and their slit diaphragms ensure the integrity of the renal basement membrane that forms the barrier to urinary protein loss. A putative disruption of the slit diaphragm and its main protein components, nephrin and Podocin, may be implicated in the pathogenesis of lupus nephritis (LN). We studied the glomerular protein expression of nephrin and Podocin in NZB/W LN mice by Western blot and immunofluorescence; mRNA levels were measured by real-time PCR. Human kidney biopsies of class II (n = 5), IV (n = 4), V (n = 7) LN were evaluated for nephrin expression by immunohistochemistry. Glomerular protein expression of nephrin and Podocin were significantly reduced in NZB/W LN, starting from the earlier stages (mild mesangial LN) and becoming pronounced at advanced histological forms (focal and diffuse proliferative LN). Nephrin and Podocin mRNA levels were substantially decreased in diffuse proliferative disease. Decreased expression of both proteins correlated with electron microscopy findings ...
Yan Xing - One of the best experts on this subject based on the ideXlab platform.
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R168H and V165X mutant Podocin might induce different degrees of podocyte injury via different molecular mechanisms
Genes to cells : devoted to molecular & cellular mechanisms, 2009Co-Authors: Qingfeng Fan, Yan Xing, Jie Ding, Han Zhang, Shufang Liu, Jing Miao, Na GuanAbstract:A lot of mutations of Podocin, a key protein of podocyte slit diaphragm (SD), have been found both in hereditary and sporadic focal segmental glomeruloscleorosis (FSGS). Nevertheless, the mechanisms of podocyte injury induced by mutant Podocins are still unclear. A compound heterozygous Podocin mutation was identified in our FSGS patient, leading to a truncated (Podocin V165X) and a missense mutant protein (Podocin R168H), respectively. Here, it was explored whether and how both mutant Podocins induce podocyte injury in the in vitro cultured podocyte cell line. Our results showed that Podocin R168H induced more significant podocyte apoptosis and expression changes in more podocyte molecules than Podocin V165X. Podocyte injury caused by the normal localized PodocinV165X was effectively inhibited by TRPC6 knockdown. The abnormal retention of PodocinR168H in endoplasmic reticulum (ER) resulted in the mis-localizations of other critical SD molecules nephrin, CD2AP and TRPC6, and significantly up-regulated ER stress markers Bip/grp78, p-PERK and caspase-12. These results implicated that Podocin R168H and Podocin V165X induced different degrees of podocyte injury, which might be resulted from different molecular mechanisms. Our findings provided some possible clues for further exploring the pharmacological targets to the proteinuria induced by different mutant Podocins.
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the relationship among nephrin Podocin cd2ap and α actinin might not be a true interaction in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1 , NPHS2 , CD2AP , and ACTN4 , can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or α -actinin-4 mRNA by using reconstructed RNA interference vector – psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of α -actinin-4, whereas α -actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
-
the relationship among nephrin Podocin cd2ap and alpha actinin might not be a true interaction in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:: The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1, NPHS2, CD2AP, and ACTN4, can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or alpha-actinin-4 mRNA by using reconstructed RNA interference vector--psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of alpha-actinin-4, whereas alpha-actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
-
the relationship among nephrin Podocin cd2ap and alpha actinin might not be a true lsquo interaction rsquo in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1, NPHS2, CD2AP, and ACTN4, can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or -actinin-4 mRNA by using reconstructed RNA interference vector – psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of -actinin-4, whereas -actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
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Original ArticleThe relationship among nephrin, Podocin, CD2AP, and α-actinin might not be a true ‘interaction’ in podocyte
Kidney International, 2006Co-Authors: Yan Xing, N. Guan, J Ding, Jinsheng ZhangAbstract:The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1 , NPHS2 , CD2AP , and ACTN4 , can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, Podocin, CD2AP, or α -actinin-4 mRNA by using reconstructed RNA interference vector – psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas Podocin showed no change. Contrarily, with Podocin or CD2AP knockdown, nephrin decreased, while CD2AP or Podocin increased. Nephrin, Podocin, or CD2AP knockdown did not change the expression of α -actinin-4, whereas α -actinin-4 knockdown begetted the reduction of nephrin, and the increment of Podocin and CD2AP. The redistributions of nephrin, Podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.