The Experts below are selected from a list of 3336 Experts worldwide ranked by ideXlab platform
James R. Cavey - One of the best experts on this subject based on the ideXlab platform.
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characterization of a non uba domain missense mutation of Sequestosome 1 sqstm1 in paget s disease of bone
Journal of Bone and Mineral Research, 2009Co-Authors: Dereen Najat, Thomas P. Garner, Thilo Hagen, Barry Shaw, Paul W. Sheppard, Alberto Falchetti, Francesca Marini, Maria L. Brandi, Jed Long, James R. CaveyAbstract:Mutations affecting the ubiquitin-associated (UBA) domain of Sequestosome 1 (SQSTM1/p62) are commonly found in Paget's disease of bone (PDB) and impair SQSTM1's ability to bind ubiquitin, resulting in dysregulated NF-κB signaling. In contrast, non-UBA domain mutations are rarer, and little is known about how they manifest their effects. We present the first characterization at the molecular, cellular, and functional level of a non-UBA domain missense mutation (A381V) of SQSTM1. Direct sequencing of exon 7 of the SQSTM1 gene in an Italian PDB patient detected a heterozygous C to T transversion at position 1182, resulting in an alanine to valine substitution at codon 381. Pull-down assays showed the non-UBA region of SQSTM1 that contains A381 is important in mediating ubiquitin-binding affinity and that the A381V mutation exerts weak negative effects on ubiquitin binding. Structural and binding analyses of longer UBA constructs containing A381, using NMR spectroscopy and circular dichroism, showed this region of the protein to be largely unstructured and confirmed its contribution to increased ubiquitin-binding affinity. Co-transfections of U20S cells showed that the A381V mutant SQSTM1 co-localized with ubiquitin with a cellular phenotype indistinguishable from wildtype. Finally, effects of the wildtype and mutant SQSTM1 on NF-κB signaling were assessed in HEK293 cells co-transfected with an NF-κB luciferase reporter construct. A381V mutant SQSTM1 produced a level of activation of NF-κB signaling greater than wildtype and similar to that of UBA domain mutants, indicating that non-UBA and UBA domain mutations may exert their effects through a common mechanism involving dysregulated NF-κB signaling.
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Characterization of a Non‐UBA Domain Missense Mutation of Sequestosome 1 (SQSTM1) in Paget's Disease of Bone
Journal of Bone and Mineral Research, 2009Co-Authors: Dereen Najat, Thomas P. Garner, Thilo Hagen, Barry Shaw, Paul W. Sheppard, Alberto Falchetti, Francesca Marini, Maria L. Brandi, Jed Long, James R. CaveyAbstract:Mutations affecting the ubiquitin-associated (UBA) domain of Sequestosome 1 (SQSTM1/p62) are commonly found in Paget's disease of bone (PDB) and impair SQSTM1's ability to bind ubiquitin, resulting in dysregulated NF-κB signaling. In contrast, non-UBA domain mutations are rarer, and little is known about how they manifest their effects. We present the first characterization at the molecular, cellular, and functional level of a non-UBA domain missense mutation (A381V) of SQSTM1. Direct sequencing of exon 7 of the SQSTM1 gene in an Italian PDB patient detected a heterozygous C to T transversion at position 1182, resulting in an alanine to valine substitution at codon 381. Pull-down assays showed the non-UBA region of SQSTM1 that contains A381 is important in mediating ubiquitin-binding affinity and that the A381V mutation exerts weak negative effects on ubiquitin binding. Structural and binding analyses of longer UBA constructs containing A381, using NMR spectroscopy and circular dichroism, showed this region of the protein to be largely unstructured and confirmed its contribution to increased ubiquitin-binding affinity. Co-transfections of U20S cells showed that the A381V mutant SQSTM1 co-localized with ubiquitin with a cellular phenotype indistinguishable from wildtype. Finally, effects of the wildtype and mutant SQSTM1 on NF-κB signaling were assessed in HEK293 cells co-transfected with an NF-κB luciferase reporter construct. A381V mutant SQSTM1 produced a level of activation of NF-κB signaling greater than wildtype and similar to that of UBA domain mutants, indicating that non-UBA and UBA domain mutations may exert their effects through a common mechanism involving dysregulated NF-κB signaling.
J. Coen Netelenbos - One of the best experts on this subject based on the ideXlab platform.
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Sporadic Hyperphosphatasia Syndrome Featuring Periostitis and Accelerated Skeletal Turnover without Receptor Activator of Nuclear Factor-κB, Osteoprotegerin, or Sequestosome-1 Gene Defects
The Journal of Clinical Endocrinology & Metabolism, 2007Co-Authors: Suat Simsek, Natalja M. Basoski, Nathalie Bravenboer, Xiafang Zhang, Steven Mumm, Michael P. Whyte, J. Coen NetelenbosAbstract:Context: A middle-aged woman with recent-onset painful swollen fingers and widespread periostitis, elevated serum alkaline phosphatase (ALP) activity and erythrocyte sedimentation rate, and accelerated skeletal turnover was found not to have mutations in the gene sequences for exon 1 of receptor activator of nuclear factor-κB (RANK), osteoprotegerin (OPG), or Sequestosome-1. Introduction: Hyperphosphatasia refers to disorders that feature elevated serum ALP activity (hyperphosphatasemia) usually from excesses of the bone isoform of ALP. Such conditions include familial expansile osteolysis, expansile skeletal hyperphosphatasia, and a familial form of early-onset Paget’s disease of bone (PDB2), all from constitutive activation of RANK, and juvenile Paget’s disease from OPG deficiency. Patient and Methods: A 38-yr-old woman developed painful swollen fingers and achy bones after an episode of unexplained pericarditis and restrictive lung disease. Sequence analysis of exon 1 of TNFRSF11A encoding RANK, TNFRSF...
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Sporadic Hyperphosphatasia Syndrome Featuring Periostitis and Accelerated Skeletal Turnover without Receptor Activator of Nuclear Factor-κB, Osteoprotegerin, or Sequestosome-1 Gene Defects
The Journal of clinical endocrinology and metabolism, 2007Co-Authors: Suat Simsek, Natalja M. Basoski, Nathalie Bravenboer, Xiafang Zhang, Steven Mumm, Michael P. Whyte, J. Coen NetelenbosAbstract:A middle-aged woman with recent-onset painful swollen fingers and widespread periostitis, elevated serum alkaline phosphatase (ALP) activity and erythrocyte sedimentation rate, and accelerated skeletal turnover was found not to have mutations in the gene sequences for exon 1 of receptor activator of nuclear factor-kappaB (RANK), osteoprotegerin (OPG), or Sequestosome-1. Hyperphosphatasia refers to disorders that feature elevated serum ALP activity (hyperphosphatasemia) usually from excesses of the bone isoform of ALP. Such conditions include familial expansile osteolysis, expansile skeletal hyperphosphatasia, and a familial form of early-onset Paget's disease of bone (PDB2), all from constitutive activation of RANK, and juvenile Paget's disease from OPG deficiency. A 38-yr-old woman developed painful swollen fingers and achy bones after an episode of unexplained pericarditis and restrictive lung disease. Sequence analysis of exon 1 of TNFRSF11A encoding RANK, TNFRSF11B encoding OPG, and SQSTM1 encoding Sequestosome-1 searched for mutations responsible for familial expansile osteolysis, expansile skeletal hyperphosphatasia, or PDB2, juvenile Paget's disease, or Paget's disease of bone (PDB), respectively. Serum ALP and osteocalcin and urinary hydroxyproline were increased. Radiographs showed widespread, symmetric hyperostosis in the limbs where bone scintigraphy demonstrated enhanced radionuclide uptake. Iliac crest histology revealed accelerated skeletal turnover. No mutations were detected in the three genes examined. Three years of therapy with 70 mg alendronate orally once weekly improved symptoms, radiographic abnormalities, and biochemical markers. Our patient manifested a unique, sporadic hyperphosphatasia syndrome. Unexplained, transient inflammation seemed to cause her pericarditis, restrictive lung disease, and periostitis with accelerated skeletal turnover that responded well to antiinflammatory drugs and alendronate therapy.
Dereen Najat - One of the best experts on this subject based on the ideXlab platform.
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characterization of a non uba domain missense mutation of Sequestosome 1 sqstm1 in paget s disease of bone
Journal of Bone and Mineral Research, 2009Co-Authors: Dereen Najat, Thomas P. Garner, Thilo Hagen, Barry Shaw, Paul W. Sheppard, Alberto Falchetti, Francesca Marini, Maria L. Brandi, Jed Long, James R. CaveyAbstract:Mutations affecting the ubiquitin-associated (UBA) domain of Sequestosome 1 (SQSTM1/p62) are commonly found in Paget's disease of bone (PDB) and impair SQSTM1's ability to bind ubiquitin, resulting in dysregulated NF-κB signaling. In contrast, non-UBA domain mutations are rarer, and little is known about how they manifest their effects. We present the first characterization at the molecular, cellular, and functional level of a non-UBA domain missense mutation (A381V) of SQSTM1. Direct sequencing of exon 7 of the SQSTM1 gene in an Italian PDB patient detected a heterozygous C to T transversion at position 1182, resulting in an alanine to valine substitution at codon 381. Pull-down assays showed the non-UBA region of SQSTM1 that contains A381 is important in mediating ubiquitin-binding affinity and that the A381V mutation exerts weak negative effects on ubiquitin binding. Structural and binding analyses of longer UBA constructs containing A381, using NMR spectroscopy and circular dichroism, showed this region of the protein to be largely unstructured and confirmed its contribution to increased ubiquitin-binding affinity. Co-transfections of U20S cells showed that the A381V mutant SQSTM1 co-localized with ubiquitin with a cellular phenotype indistinguishable from wildtype. Finally, effects of the wildtype and mutant SQSTM1 on NF-κB signaling were assessed in HEK293 cells co-transfected with an NF-κB luciferase reporter construct. A381V mutant SQSTM1 produced a level of activation of NF-κB signaling greater than wildtype and similar to that of UBA domain mutants, indicating that non-UBA and UBA domain mutations may exert their effects through a common mechanism involving dysregulated NF-κB signaling.
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Characterization of a Non‐UBA Domain Missense Mutation of Sequestosome 1 (SQSTM1) in Paget's Disease of Bone
Journal of Bone and Mineral Research, 2009Co-Authors: Dereen Najat, Thomas P. Garner, Thilo Hagen, Barry Shaw, Paul W. Sheppard, Alberto Falchetti, Francesca Marini, Maria L. Brandi, Jed Long, James R. CaveyAbstract:Mutations affecting the ubiquitin-associated (UBA) domain of Sequestosome 1 (SQSTM1/p62) are commonly found in Paget's disease of bone (PDB) and impair SQSTM1's ability to bind ubiquitin, resulting in dysregulated NF-κB signaling. In contrast, non-UBA domain mutations are rarer, and little is known about how they manifest their effects. We present the first characterization at the molecular, cellular, and functional level of a non-UBA domain missense mutation (A381V) of SQSTM1. Direct sequencing of exon 7 of the SQSTM1 gene in an Italian PDB patient detected a heterozygous C to T transversion at position 1182, resulting in an alanine to valine substitution at codon 381. Pull-down assays showed the non-UBA region of SQSTM1 that contains A381 is important in mediating ubiquitin-binding affinity and that the A381V mutation exerts weak negative effects on ubiquitin binding. Structural and binding analyses of longer UBA constructs containing A381, using NMR spectroscopy and circular dichroism, showed this region of the protein to be largely unstructured and confirmed its contribution to increased ubiquitin-binding affinity. Co-transfections of U20S cells showed that the A381V mutant SQSTM1 co-localized with ubiquitin with a cellular phenotype indistinguishable from wildtype. Finally, effects of the wildtype and mutant SQSTM1 on NF-κB signaling were assessed in HEK293 cells co-transfected with an NF-κB luciferase reporter construct. A381V mutant SQSTM1 produced a level of activation of NF-κB signaling greater than wildtype and similar to that of UBA domain mutants, indicating that non-UBA and UBA domain mutations may exert their effects through a common mechanism involving dysregulated NF-κB signaling.
Suat Simsek - One of the best experts on this subject based on the ideXlab platform.
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Sporadic Hyperphosphatasia Syndrome Featuring Periostitis and Accelerated Skeletal Turnover without Receptor Activator of Nuclear Factor-κB, Osteoprotegerin, or Sequestosome-1 Gene Defects
The Journal of Clinical Endocrinology & Metabolism, 2007Co-Authors: Suat Simsek, Natalja M. Basoski, Nathalie Bravenboer, Xiafang Zhang, Steven Mumm, Michael P. Whyte, J. Coen NetelenbosAbstract:Context: A middle-aged woman with recent-onset painful swollen fingers and widespread periostitis, elevated serum alkaline phosphatase (ALP) activity and erythrocyte sedimentation rate, and accelerated skeletal turnover was found not to have mutations in the gene sequences for exon 1 of receptor activator of nuclear factor-κB (RANK), osteoprotegerin (OPG), or Sequestosome-1. Introduction: Hyperphosphatasia refers to disorders that feature elevated serum ALP activity (hyperphosphatasemia) usually from excesses of the bone isoform of ALP. Such conditions include familial expansile osteolysis, expansile skeletal hyperphosphatasia, and a familial form of early-onset Paget’s disease of bone (PDB2), all from constitutive activation of RANK, and juvenile Paget’s disease from OPG deficiency. Patient and Methods: A 38-yr-old woman developed painful swollen fingers and achy bones after an episode of unexplained pericarditis and restrictive lung disease. Sequence analysis of exon 1 of TNFRSF11A encoding RANK, TNFRSF...
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Sporadic Hyperphosphatasia Syndrome Featuring Periostitis and Accelerated Skeletal Turnover without Receptor Activator of Nuclear Factor-κB, Osteoprotegerin, or Sequestosome-1 Gene Defects
The Journal of clinical endocrinology and metabolism, 2007Co-Authors: Suat Simsek, Natalja M. Basoski, Nathalie Bravenboer, Xiafang Zhang, Steven Mumm, Michael P. Whyte, J. Coen NetelenbosAbstract:A middle-aged woman with recent-onset painful swollen fingers and widespread periostitis, elevated serum alkaline phosphatase (ALP) activity and erythrocyte sedimentation rate, and accelerated skeletal turnover was found not to have mutations in the gene sequences for exon 1 of receptor activator of nuclear factor-kappaB (RANK), osteoprotegerin (OPG), or Sequestosome-1. Hyperphosphatasia refers to disorders that feature elevated serum ALP activity (hyperphosphatasemia) usually from excesses of the bone isoform of ALP. Such conditions include familial expansile osteolysis, expansile skeletal hyperphosphatasia, and a familial form of early-onset Paget's disease of bone (PDB2), all from constitutive activation of RANK, and juvenile Paget's disease from OPG deficiency. A 38-yr-old woman developed painful swollen fingers and achy bones after an episode of unexplained pericarditis and restrictive lung disease. Sequence analysis of exon 1 of TNFRSF11A encoding RANK, TNFRSF11B encoding OPG, and SQSTM1 encoding Sequestosome-1 searched for mutations responsible for familial expansile osteolysis, expansile skeletal hyperphosphatasia, or PDB2, juvenile Paget's disease, or Paget's disease of bone (PDB), respectively. Serum ALP and osteocalcin and urinary hydroxyproline were increased. Radiographs showed widespread, symmetric hyperostosis in the limbs where bone scintigraphy demonstrated enhanced radionuclide uptake. Iliac crest histology revealed accelerated skeletal turnover. No mutations were detected in the three genes examined. Three years of therapy with 70 mg alendronate orally once weekly improved symptoms, radiographic abnormalities, and biochemical markers. Our patient manifested a unique, sporadic hyperphosphatasia syndrome. Unexplained, transient inflammation seemed to cause her pericarditis, restrictive lung disease, and periostitis with accelerated skeletal turnover that responded well to antiinflammatory drugs and alendronate therapy.
Marie W. Wooten - One of the best experts on this subject based on the ideXlab platform.
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Sequestosome 1/p62 links familial ALS mutant SOD1 to LC3 via an ubiquitin-independent mechanism.
Journal of Neurochemistry, 2009Co-Authors: Jozsef Gal, Marie W. Wooten, Anna-lena Ström, David M. Kwinter, Renee Kilty, Jiayu Zhang, Ping Shi, Haining ZhuAbstract:The p62/Sequestosome 1 protein has been identified as a component of pathological protein inclusions in neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). P62 has also been implicated in autophagy, a process of mass degradation of intracellular proteins and organelles. Autophagy is a critical pathway for degrading misfolded and/or damaged proteins, including the copper-zinc superoxide dismutase (SOD1) mutants linked to familial ALS. We previously reported that p62 interacted with ALS mutants of SOD1 and that the ubiquitin-association domain of p62 was dispensable for the interaction. In this study, we identified two distinct regions of p62 that were essential to its binding to mutant SOD1: the N-terminal Phox and Bem1 (PB1) domain (residues 1-104) and a separate internal region (residues 178-224) termed here as SOD1 mutant interaction region (SMIR). The PB1 domain is required for appropriate oligomeric status of p62 and the SMIR is the actual region interacting with mutant SOD1. Within the SMIR, the conserved W184, H190 and positively charged R183, R186, K187, and K189 residues are critical to the p62-mutant SOD1 interaction as substitution of these residues with alanine resulted in significantly abolished binding. In addition, SMIR and the p62 sequence responsible for the interaction with LC3, a protein essential for autophagy activation, are independent of each other. In cells lacking p62, the existence of mutant SOD1 in acidic autolysosomes decreased, suggesting that p62 can function as an adaptor between mutant SOD1 and the autophagy machinery. This study provides a novel molecular mechanism by which mutant SOD1 can be recognized by p62 in an ubiquitin-independent fashion and targeted for the autophagy-lysosome degradation pathway.
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Essential role of Sequestosome 1/p62 in regulating accumulation of Lys63-ubiquitinated proteins.
Journal of Biological Chemistry, 2008Co-Authors: Marie W. Wooten, Thangiah Geetha, M. Lamar Seibenhener, J. Ramesh Babu, Junmin Peng, Nancy J. Cox, Maria-t. Diaz-meco, Jorge MoscatAbstract:Abstract Sequestosome 1 (SQSTM1)/p62 is an interacting partner of the atypical protein kinase C ζ/ι and serves as a scaffold for cell signaling and ubiquitin binding, which is critical for several cell functions in vivo such as osteoclastogenesis, adipogenesis, and T cell activation. Here we report that in neurons of p62–/– mouse brain there is a detectable increase in ubiquitin staining paralleled by accumulation of insoluble ubiquitinated proteins. The absolute amount of each ubiquitin chain linkage measured by quantitative mass spectrometry demonstrated hyperaccumulation of Lys63 chains in the insoluble fraction recovered from the brain of p62–/– mice, which correlated with increased levels of Lys63-ubiquitinated TrkA receptor. The increase in Lys63 chains was attributed in part to diminished activity of the TRAF6-interacting the Lys63-deubiquitinating enzyme (DUB), cylindromatosis tumor suppressor (CYLD). The interaction of CYLD with TRAF6 was dependent upon p62, thus defining a mechanism that accounts for decreased activity of CYLD in the absence of p62. These findings reveal that p62 serves as an adapter for the formation of this complex, thereby regulating the DUB activity of CYLD by TRAF6 interaction. Thus, p62 has a bifunctional role in regulation of an E3 ubiquitin-protein ligase, TRAF6, and a DUB, CYLD, to balance the turnover of Lys63-polyubiquitinated proteins such as TrkA.
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Essential role of Sequestosome 1/p62 in regulating accumulation of Lys63-ubiquitinated proteins.
The Journal of biological chemistry, 2008Co-Authors: Marie W. Wooten, Thangiah Geetha, M. Lamar Seibenhener, J. Ramesh Babu, Junmin Peng, Nancy J. Cox, Maria-t. Diaz-meco, Jorge MoscatAbstract:Sequestosome 1 (SQSTM1)/p62 is an interacting partner of the atypical protein kinase C zeta/iota and serves as a scaffold for cell signaling and ubiquitin binding, which is critical for several cell functions in vivo such as osteoclastogenesis, adipogenesis, and T cell activation. Here we report that in neurons of p62-/- mouse brain there is a detectable increase in ubiquitin staining paralleled by accumulation of insoluble ubiquitinated proteins. The absolute amount of each ubiquitin chain linkage measured by quantitative mass spectrometry demonstrated hyperaccumulation of Lys63 chains in the insoluble fraction recovered from the brain of p62-/- mice, which correlated with increased levels of Lys63-ubiquitinated TrkA receptor. The increase in Lys63 chains was attributed in part to diminished activity of the TRAF6-interacting the Lys63-deubiquitinating enzyme (DUB), cylindromatosis tumor suppressor (CYLD). The interaction of CYLD with TRAF6 was dependent upon p62, thus defining a mechanism that accounts for decreased activity of CYLD in the absence of p62. These findings reveal that p62 serves as an adapter for the formation of this complex, thereby regulating the DUB activity of CYLD by TRAF6 interaction. Thus, p62 has a bifunctional role in regulation of an E3 ubiquitin-protein ligase, TRAF6, and a DUB, CYLD, to balance the turnover of Lys63-polyubiquitinated proteins such as TrkA.
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Sequestosome 1 p62 more than just a scaffold
FEBS Letters, 2007Co-Authors: Lamar M Seibenhener, Thangiah Geetha, Marie W. WootenAbstract:The interaction of proteins with ubiquitin receptors is key to solving the mystery that surrounds the functional role ubiquitin chains play in directing traffic. The specificity of these interactions is largely mediated by UbL/UBA domains. Sequestosome 1/p62 is a protein that is gaining attention as it is intimately involved in cell signaling, receptor internalization, and protein turnover. Herein we review recent advances in the field.
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Sequestosome 1/p62 – More than just a scaffold
FEBS Letters, 2006Co-Authors: M. Lamar Seibenhener, Thangiah Geetha, Marie W. WootenAbstract:The interaction of proteins with ubiquitin receptors is key to solving the mystery that surrounds the functional role ubiquitin chains play in directing traffic. The specificity of these interactions is largely mediated by UbL/UBA domains. Sequestosome 1/p62 is a protein that is gaining attention as it is intimately involved in cell signaling, receptor internalization, and protein turnover. Herein we review recent advances in the field.
