The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Joan C Marini - One of the best experts on this subject based on the ideXlab platform.
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New perspectives on osteogenesis imperfecta
Nature Reviews Endocrinology, 2011Co-Authors: Antonella Forlino, Aileen M Barnes, Wayne A Cabral, Joan C MariniAbstract:Osteogenesis imperfecta, or 'brittle bone disease', is a clinically heterogeneous heritable connective tissue disorder, the causative defects of which are directly related to type I Collagen. Human cases and murine models of osteogenesis imperfecta are providing insight into common pathways in dominant and recessive osteogenesis imperfecta, leading to the re-evaluation of its definition, classification and therapeutic approaches. A new paradigm has emerged for osteogenesis imperfecta as a Collagen-related disorder. The more prevalent autosomal dominant forms of osteogenesis imperfecta are caused by primary defects in type I Collagen, whereas autosomal recessive forms are caused by deficiency of proteins which interact with type I proCollagen for post-translational modification and/or folding. Factors that contribute to the mechanism of dominant osteogenesis imperfecta include intracellular stress, disruption of interactions between Collagen and nonCollagenous proteins, compromised matrix structure, abnormal cell–cell and cell–matrix interactions and tissue mineralization. Recessive osteogenesis imperfecta is caused by deficiency of any of the three components of the Collagen prolyl 3-hydroxylation complex. Absence of 3-hydroxylation is associated with increased modification of the Collagen Helix, consistent with delayed Collagen folding. Other causes of recessive osteogenesis imperfecta include deficiency of the Collagen chaperones FKBP10 or Serpin H1. Murine models are crucial to uncovering the common pathways in dominant and recessive osteogenesis imperfecta bone dysplasia. Clinical management of osteogenesis imperfecta is multidisciplinary, encompassing substantial progress in physical rehabilitation and surgical procedures, management of hearing, dental and pulmonary abnormalities, as well as drugs, such as bisphosphonates and recombinant human growth hormone. Novel treatments using cell therapy or new drug regimens hold promise for the future. Osteogenesis imperfecta is a Collagen-related disorder characterized by low bone mass, decreased bone strength and increased bone fragility Dominant osteogenesis imperfecta is caused by defects in the quantity or structure of type I proCollagen, which affects bone at multiple levels, for example, matrix structure and mineralization Recessive osteogenesis imperfecta is caused by deficiency of proteins that interact with Collagen and affect its post-translational modification or folding, such as CRTAP, P3H1 and PPIB and Serpin H1 and FKBP10 Common features of dominant and recessive osteogenesis imperfecta, for example, delayed Collagen folding, effects on bone and cartilage or increased endoplasmic reticulum stress, may be the key to understanding its pathogenesis Clinical management of osteogenesis imperfecta should involve a multidisciplinary team that provides physical rehabilitation, genetic, hearing, dental, neurological, endocrine and surgical management Bisphosphonates are widely administered to individuals with osteogenesis imperfecta, with positive effects on bone mass and vertebral geometry, but cause a decline in bone material quality
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Null mutations in LEPRE1 and CRTAP cause severe recessive osteogenesis imperfecta
Cell and Tissue Research, 2010Co-Authors: Joan C Marini, Wayne A Cabral, Aileen M BarnesAbstract:Classical osteogenesis imperfecta (OI) is a dominant genetic disorder of connective tissue caused by mutations in either of the two genes encoding type I Collagen, COL1A1 and COL1A2 . Recent investigations, however, have generated a new paradigm for OI incorporating many of the prototypical features that distinguish dominant and recessive conditions, within a type I Collagen framework. We and others have shown that the long-sought cause of the recessive form of OI, first postulated in the Sillence classification, lies in defects in the genes encoding cartilage-associated protein ( CRTAP ) or prolyl 3-hydroxylase 1 (P3H1/ LEPRE1 ). Together with cyclophilin B ( PPIB ), CRTAP and P3H1 comprise the Collagen prolyl 3-hydroxylation complex, which catalyzes a specific posttranslational modification of types I, II, and V Collagen, and may act as a general chaperone. Patients with mutations in CRTAP or LEPRE1 have a lethal to severe osteochondrodystrophy that overlaps with Sillence types II and III OI but has distinctive features. Infants with recessive OI have white sclerae, undertubulation of the long bones, gracile ribs without beading, and a small to normal head circumference. Those who survive to childhood or the teen years have severe growth deficiency and extreme bone fragility. Most causative mutations result in null alleles, with the absence or severe reduction of gene transcripts and proteins. As expected, 3-hydroxylation of the Pro986 residue is absent or severly reduced, but bone severity and survival length do not correlate with the extent of residual hydroxylation. Surprisingly, the Collagen produced by cells with an absence of Pro986 hydroxylation has helical overmodification by lysyl hydroxylase and prolyl 4-hydroxylase, indicating that the folding of the Collagen Helix has been substantially delayed.
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Y-position cysteine substitution in type I Collagen (alpha1(I) R888C/p.R1066C) is associated with osteogenesis imperfecta/Ehlers-Danlos syndrome phenotype
Human mutation, 2007Co-Authors: Wayne A Cabral, Sergey Leikin, Elena Makareeva, Douglas R. Keene, Anne D. Letocha, Nina Scribanu, Andrzej Fertala, Andrzej Steplewski, Anton V. Persikov, Joan C MariniAbstract:The most common mutations in type I Collagen causing types II-IV osteogenesis imperfecta (OI) result in substitution for glycine in a Gly-Xaa-Yaa triplet by another amino acid. We delineated a Y-position substitution in a small pedigree with a combined OI/Ehlers-Danlos Syndrome (EDS) phenotype, characterized by moderately decreased DEXA z-score (-1.3 to -2.6), long bone fractures, and large-joint hyperextensibility. Affected individuals have an alpha1(I)R888C (p.R1066C) substitution in one COL1A1 allele. Polyacrylamide gel electrophoresis (PAGE) of [(3)H]-proline labeled steady-state Collagen reveals slight overmodification of the alpha1(I) monomer band, much less than expected for a substitution of a neighboring glycine residue, and a faint alpha1(I) dimer. Dimers form in about 10% of proband type I Collagen. Dimer formation is inefficient compared to a possible 25%, probably because the SH-side chains have less proximity in this Y-position than when substituting for a glycine. Theoretical stability calculations, differential scanning calorimetry (DSC) thermograms, and thermal denaturation curves showed only weak local destabilization from the Y-position substitution in one or two chains of a Collagen Helix, but greater destabilization is seen in Collagen containing dimers. Y-position Collagen dimers cause kinking of the Helix, resulting in a register shift that is propagated the full length of the Helix and causes resistance to proCollagen processing by N-proteinase. Collagen containing the Y-position substitution is incorporated into matrix deposited in culture, including immaturely and maturely cross-linked fractions. In vivo, proband dermal fibrils have decreased density and increased diameter compared to controls, with occasional aggregate formation. This report on Y-position substitutions in type I Collagen extends the range of phenotypes caused by nonglycine substitutions and shows that, similar to X- and Y-position substitutions in types II and III Collagen, the phenotypes resulting from nonglycine substitutions in type I Collagen are distinct from those caused by glycine substitutions.
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type i Collagen triplet duplication mutation in lethal osteogenesis imperfecta shifts register of α chains throughout the Helix and disrupts incorporation of mutant helices into fibrils and extracellular matrix
Journal of Biological Chemistry, 2003Co-Authors: Wayne A Cabral, Sergey Leikin, Elena Makareeva, Marianna V Mertts, Alain Colige, Mustafa Tekin, Arti Pandya, Joan C MariniAbstract:Abstract The majority of Collagen mutations causing osteogenesis imperfecta (OI) are glycine substitutions that disrupt formation of the triple Helix. A rare type of Collagen mutation consists of a duplication or deletion of one or two Gly-X-Y triplets. These mutations shift the register of Collagen chains with respect to each other in the Helix but do not interrupt the triplet sequence, yet they have severe clinical consequences. We investigated the effect of shifting the register of the Collagen Helix by a single Gly-X-Y triplet on Collagen assembly, stability, and incorporation into fibrils and matrix. These studies utilized a triplet duplication in COL1A1 exon 44 that occurred in the cDNA and gDNA of two siblings with lethal OI. The normal allele encodes three identical Gly-Ala-Hyp triplets at aa 868–876, whereas the mutant allele encodes four. The register shift delays Helix formation, causing overmodification. Differential scanning calorimetry yielded a decrease in T m of 2 °C for helices with one mutant chain and a 6 °C decrease in helices with two mutant chains. An in vitro binary co-processing assay of N-proteinase cleavage demonstrated that proCollagen with the triplet duplication has slower N-propeptide cleavage than in normal controls or proCollagen with proα1(I) G832S, G898S, or G997S substitutions, showing that the register shift persists through the entire Helix. The register shift disrupts incorporation of mutant Collagen into fibrils and matrix. Proband fibrils formed inefficiently in vitroand contained only normal helices and helices with a single mutant chain. Helices with two mutant chains and a significant portion of helices with one mutant chain did not form fibrils. In matrix deposited by proband fibroblasts, mutant chains were abundant in the immaturely cross-linked fraction but constituted a minor fraction of maturely cross-linked chains. The profound effects of shifting the Collagen triplet register on chain interactions in the Helix and on fibril formation correlate with the severe clinical consequences.
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G76E Substitution in Type I Collagen Is the First Nonlethal Glutamic Acid Substitution in the α1(I) Chain and Alters Folding of the N-terminal End of the Helix
Molecular genetics and metabolism, 2001Co-Authors: Wayne A Cabral, Edith J. Chernoff, Joan C MariniAbstract:Abstract The majority of osteogenesis imperfecta (OI) is caused by substitutions for glycine residues in the two α chains of type I Collagen. Since only 4% of possible nucleotide changes in type I Collagen glycine codons would result in a glutamic acid substitution, these are predicted to be infrequent. Only one glutamic acid substitution in type I Collagen has been fully reported. We describe here the clinical, biochemical, and molecular characterization of a girl with severe type III OI caused by a G76E substitution in COL1A1. This is the first delineation of a glutamic acid substitution in the α1(I) chain causing nonlethal osteogenesis imperfecta. The proband's fibroblast type I Collagen chains and cyanogen bromide peptides were electrophoretically normal, while osteoblast Collagen was slightly overmodified. This suggested a mutation near the N-terminal end of the Collagen Helix. A mismatch was detected by RNA:DNA hybrid analysis in cDNA coding for 106 amino acids at the N-terminal end of the helical region. Subclones of both alleles were sequenced and revealed a G → A (c.761G > A) mutation causing an α1(I) G76E substitution in one allele. The presence of the mutation in the proband's leukocyte gDNA, and its absence in parental gDNA, was confirmed by Tsp509I digestion. The glutamic acid substitution alters the folding of the mutant Collagen helices. Pericellular processing of type I Collagen by the proband's fibroblasts yielded an earlier appearance of the pC-α1(I) form and of mature α chains as compared to control cell processing. Also, the presence of the glutamic acid substitution apparently exposes the adjacent Arg75 residue in the α1 chain. Trypsin digestion of proband fibroblast Collagen resulted in shortened α1 chains, as confirmed by CNBr analysis. In addition, the Tm for mutant helices from fibroblasts and osteoblasts was decreased 2–4°C versus controls, demonstrating a decrease in Helix stability. These findings increase our understanding of the disruptive effect of glutamic acid substitutions in Collagen.
Wayne A Cabral - One of the best experts on this subject based on the ideXlab platform.
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COL1A1 C-propeptide mutations cause ER mislocalization of proCollagen and impair C-terminal proCollagen processing.
Biochimica et biophysica acta. Molecular basis of disease, 2019Co-Authors: Aileen M Barnes, Wayne A Cabral, Maryann Weis, Elena Makareeva, Aarthi Ashok, Marina Brusel, Catherine Moali, Emmanuel Bettler, David R. Eyre, John CassellaAbstract:Abstract Mutations in the type I proCollagen C-propeptide occur in ~6.5% of Osteogenesis Imperfecta (OI) patients. They are of special interest because this region of proCollagen is involved in α chain selection and folding, but is processed prior to fibril assembly and is absent in mature Collagen fibrils in tissue. We investigated the consequences of seven COL1A1 C-propeptide mutations for Collagen biochemistry in comparison to three probands with classical glycine substitutions in the Collagen Helix near the C-propeptide and a normal control. ProCollagens with C-propeptide defects showed the expected delayed chain incorporation, slow folding and overmodification. Immunofluorescence microscopy indicated that proCollagen with C-propeptide defects was mislocalized to the ER lumen, in contrast to the ER membrane localization of normal proCollagen and proCollagen with helical substitutions. Notably, pericellular processing of proCollagen with C-propeptide mutations was defective, with accumulation of pC-Collagen and/or reduced production of mature Collagen. In vitro cleavage assays with BMP-1 ± PCPE-1 confirmed impaired C-propeptide processing of proCollagens containing mutant proα1(I) chains. Overmodified Collagens were incorporated into the matrix in culture. Dermal fibrils showed alterations in average diameter and diameter variability and bone fibrils were disorganized. Altered ER-localization and reduced pericellular processing of defective C-propeptides are expected to contribute to abnormal osteoblast differentiation and matrix function, respectively.
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New perspectives on osteogenesis imperfecta
Nature Reviews Endocrinology, 2011Co-Authors: Antonella Forlino, Aileen M Barnes, Wayne A Cabral, Joan C MariniAbstract:Osteogenesis imperfecta, or 'brittle bone disease', is a clinically heterogeneous heritable connective tissue disorder, the causative defects of which are directly related to type I Collagen. Human cases and murine models of osteogenesis imperfecta are providing insight into common pathways in dominant and recessive osteogenesis imperfecta, leading to the re-evaluation of its definition, classification and therapeutic approaches. A new paradigm has emerged for osteogenesis imperfecta as a Collagen-related disorder. The more prevalent autosomal dominant forms of osteogenesis imperfecta are caused by primary defects in type I Collagen, whereas autosomal recessive forms are caused by deficiency of proteins which interact with type I proCollagen for post-translational modification and/or folding. Factors that contribute to the mechanism of dominant osteogenesis imperfecta include intracellular stress, disruption of interactions between Collagen and nonCollagenous proteins, compromised matrix structure, abnormal cell–cell and cell–matrix interactions and tissue mineralization. Recessive osteogenesis imperfecta is caused by deficiency of any of the three components of the Collagen prolyl 3-hydroxylation complex. Absence of 3-hydroxylation is associated with increased modification of the Collagen Helix, consistent with delayed Collagen folding. Other causes of recessive osteogenesis imperfecta include deficiency of the Collagen chaperones FKBP10 or Serpin H1. Murine models are crucial to uncovering the common pathways in dominant and recessive osteogenesis imperfecta bone dysplasia. Clinical management of osteogenesis imperfecta is multidisciplinary, encompassing substantial progress in physical rehabilitation and surgical procedures, management of hearing, dental and pulmonary abnormalities, as well as drugs, such as bisphosphonates and recombinant human growth hormone. Novel treatments using cell therapy or new drug regimens hold promise for the future. Osteogenesis imperfecta is a Collagen-related disorder characterized by low bone mass, decreased bone strength and increased bone fragility Dominant osteogenesis imperfecta is caused by defects in the quantity or structure of type I proCollagen, which affects bone at multiple levels, for example, matrix structure and mineralization Recessive osteogenesis imperfecta is caused by deficiency of proteins that interact with Collagen and affect its post-translational modification or folding, such as CRTAP, P3H1 and PPIB and Serpin H1 and FKBP10 Common features of dominant and recessive osteogenesis imperfecta, for example, delayed Collagen folding, effects on bone and cartilage or increased endoplasmic reticulum stress, may be the key to understanding its pathogenesis Clinical management of osteogenesis imperfecta should involve a multidisciplinary team that provides physical rehabilitation, genetic, hearing, dental, neurological, endocrine and surgical management Bisphosphonates are widely administered to individuals with osteogenesis imperfecta, with positive effects on bone mass and vertebral geometry, but cause a decline in bone material quality
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Null mutations in LEPRE1 and CRTAP cause severe recessive osteogenesis imperfecta
Cell and Tissue Research, 2010Co-Authors: Joan C Marini, Wayne A Cabral, Aileen M BarnesAbstract:Classical osteogenesis imperfecta (OI) is a dominant genetic disorder of connective tissue caused by mutations in either of the two genes encoding type I Collagen, COL1A1 and COL1A2 . Recent investigations, however, have generated a new paradigm for OI incorporating many of the prototypical features that distinguish dominant and recessive conditions, within a type I Collagen framework. We and others have shown that the long-sought cause of the recessive form of OI, first postulated in the Sillence classification, lies in defects in the genes encoding cartilage-associated protein ( CRTAP ) or prolyl 3-hydroxylase 1 (P3H1/ LEPRE1 ). Together with cyclophilin B ( PPIB ), CRTAP and P3H1 comprise the Collagen prolyl 3-hydroxylation complex, which catalyzes a specific posttranslational modification of types I, II, and V Collagen, and may act as a general chaperone. Patients with mutations in CRTAP or LEPRE1 have a lethal to severe osteochondrodystrophy that overlaps with Sillence types II and III OI but has distinctive features. Infants with recessive OI have white sclerae, undertubulation of the long bones, gracile ribs without beading, and a small to normal head circumference. Those who survive to childhood or the teen years have severe growth deficiency and extreme bone fragility. Most causative mutations result in null alleles, with the absence or severe reduction of gene transcripts and proteins. As expected, 3-hydroxylation of the Pro986 residue is absent or severly reduced, but bone severity and survival length do not correlate with the extent of residual hydroxylation. Surprisingly, the Collagen produced by cells with an absence of Pro986 hydroxylation has helical overmodification by lysyl hydroxylase and prolyl 4-hydroxylase, indicating that the folding of the Collagen Helix has been substantially delayed.
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Prolyl 3-hydroxylase 1 deficiency causes a recessive metabolic bone disorder resembling lethal/severe osteogenesis imperfecta
Nature Genetics, 2007Co-Authors: Wayne A Cabral, Aileen M Barnes, Sergey Leikin, Natalia V Kuznetsova, Weizhong Chang, Maryann Weis, Melissa A Scott, Elena Makareeva, Kenneth N Rosenbaum, Cynthia J TifftAbstract:A recessive form of severe osteogenesis imperfecta that is not caused by mutations in type I Collagen has long been suspected. Mutations in human CRTAP (cartilage-associated protein) causing recessive bone disease have been reported. CRTAP forms a complex with cyclophilin B and prolyl 3-hydroxylase 1, which is encoded by LEPRE1 and hydroxylates one residue in type I Collagen, α1(I)Pro986. We present the first five cases of a new recessive bone disorder resulting from null LEPRE1 alleles; its phenotype overlaps with lethal/severe osteogenesis imperfecta but has distinctive features. Furthermore, a mutant allele from West Africa, also found in African Americans, occurs in four of five cases. All proband LEPRE1 mutations led to premature termination codons and minimal mRNA and protein. Proband Collagen had minimal 3-hydroxylation of α1(I)Pro986 but excess lysyl hydroxylation and glycosylation along the Collagen Helix. Proband Collagen secretion was moderately delayed, but total Collagen secretion was increased. Prolyl 3-hydroxylase 1 is therefore crucial for bone development and Collagen Helix formation.
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Y-position cysteine substitution in type I Collagen (alpha1(I) R888C/p.R1066C) is associated with osteogenesis imperfecta/Ehlers-Danlos syndrome phenotype
Human mutation, 2007Co-Authors: Wayne A Cabral, Sergey Leikin, Elena Makareeva, Douglas R. Keene, Anne D. Letocha, Nina Scribanu, Andrzej Fertala, Andrzej Steplewski, Anton V. Persikov, Joan C MariniAbstract:The most common mutations in type I Collagen causing types II-IV osteogenesis imperfecta (OI) result in substitution for glycine in a Gly-Xaa-Yaa triplet by another amino acid. We delineated a Y-position substitution in a small pedigree with a combined OI/Ehlers-Danlos Syndrome (EDS) phenotype, characterized by moderately decreased DEXA z-score (-1.3 to -2.6), long bone fractures, and large-joint hyperextensibility. Affected individuals have an alpha1(I)R888C (p.R1066C) substitution in one COL1A1 allele. Polyacrylamide gel electrophoresis (PAGE) of [(3)H]-proline labeled steady-state Collagen reveals slight overmodification of the alpha1(I) monomer band, much less than expected for a substitution of a neighboring glycine residue, and a faint alpha1(I) dimer. Dimers form in about 10% of proband type I Collagen. Dimer formation is inefficient compared to a possible 25%, probably because the SH-side chains have less proximity in this Y-position than when substituting for a glycine. Theoretical stability calculations, differential scanning calorimetry (DSC) thermograms, and thermal denaturation curves showed only weak local destabilization from the Y-position substitution in one or two chains of a Collagen Helix, but greater destabilization is seen in Collagen containing dimers. Y-position Collagen dimers cause kinking of the Helix, resulting in a register shift that is propagated the full length of the Helix and causes resistance to proCollagen processing by N-proteinase. Collagen containing the Y-position substitution is incorporated into matrix deposited in culture, including immaturely and maturely cross-linked fractions. In vivo, proband dermal fibrils have decreased density and increased diameter compared to controls, with occasional aggregate formation. This report on Y-position substitutions in type I Collagen extends the range of phenotypes caused by nonglycine substitutions and shows that, similar to X- and Y-position substitutions in types II and III Collagen, the phenotypes resulting from nonglycine substitutions in type I Collagen are distinct from those caused by glycine substitutions.
Florence Ruggiero - One of the best experts on this subject based on the ideXlab platform.
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unhydroxylated triple helical Collagen i produced in transgenic plants provides new clues on the role of hydroxyproline in Collagen folding and fibril formation
Journal of Biological Chemistry, 2001Co-Authors: Stephanie Perret, Christine Merle, Simonetta Bernocco, Patricia Berland, Robert Garrone, David J S Hulmes, Manfred Theisen, Florence RuggieroAbstract:Abstract Human unhydroxylated homotrimeric triple-helical Collagen I produced in transgenic plants was used as an experimental model to provide insights into the role of hydroxyproline in molecular folding and fibril formation. By using chemically cross-linked molecules, we show here that the absence of hydroxyproline residues does not prevent correct folding of the recombinant Collagen although it markedly slows down the propagation rate compared with bovine fully hydroxylated homotrimeric Collagen I. Relatively slowcis-trans-isomerization in the absence of hydroxyproline likely represents the rate-limiting factor in the propagation of the unhydroxylated Collagen Helix. Because of the lack of hydroxylation, recombinant Collagen molecules showed increased flexibility as well as a reduced melting temperature compared with native homotrimers and heterotrimers, whereas the distribution of charged amino acids was unchanged. However, unlike with bovine Collagen I, the recombinant Collagen did not self-assemble into banded fibrils in physiological ionic strength buffer at 20 °C. Striated fibrils were only obtained with low ionic strength buffer. We propose that, under physiological ionic strength conditions, the hydroxyl groups in the native molecule retain water more efficiently thus favoring correct fibril formation. The importance of hydroxyproline in Collagen self-assembly suggested by others from the crystal structures of Collagen model peptides is thus confirmed experimentally on the entire Collagen molecule.
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Unhydroxylated triple helical Collagen I produced in transgenic plants provides new clues on the role of hydroxyproline in Collagen folding and fibril formation.
The Journal of biological chemistry, 2001Co-Authors: Stephanie Perret, Christine Merle, Simonetta Bernocco, Patricia Berland, Robert Garrone, David J S Hulmes, Manfred Theisen, Florence RuggieroAbstract:Human unhydroxylated homotrimeric triple-helical Collagen I produced in transgenic plants was used as an experimental model to provide insights into the role of hydroxyproline in molecular folding and fibril formation. By using chemically cross-linked molecules, we show here that the absence of hydroxyproline residues does not prevent correct folding of the recombinant Collagen although it markedly slows down the propagation rate compared with bovine fully hydroxylated homotrimeric Collagen I. Relatively slow cis-trans-isomerization in the absence of hydroxyproline likely represents the rate-limiting factor in the propagation of the unhydroxylated Collagen Helix. Because of the lack of hydroxylation, recombinant Collagen molecules showed increased flexibility as well as a reduced melting temperature compared with native homotrimers and heterotrimers, whereas the distribution of charged amino acids was unchanged. However, unlike with bovine Collagen I, the recombinant Collagen did not self-assemble into banded fibrils in physiological ionic strength buffer at 20 degrees C. Striated fibrils were only obtained with low ionic strength buffer. We propose that, under physiological ionic strength conditions, the hydroxyl groups in the native molecule retain water more efficiently thus favoring correct fibril formation. The importance of hydroxyproline in Collagen self-assembly suggested by others from the crystal structures of Collagen model peptides is thus confirmed experimentally on the entire Collagen molecule.
Douglas R. Keene - One of the best experts on this subject based on the ideXlab platform.
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Y-position cysteine substitution in type I Collagen (alpha1(I) R888C/p.R1066C) is associated with osteogenesis imperfecta/Ehlers-Danlos syndrome phenotype
Human mutation, 2007Co-Authors: Wayne A Cabral, Sergey Leikin, Elena Makareeva, Douglas R. Keene, Anne D. Letocha, Nina Scribanu, Andrzej Fertala, Andrzej Steplewski, Anton V. Persikov, Joan C MariniAbstract:The most common mutations in type I Collagen causing types II-IV osteogenesis imperfecta (OI) result in substitution for glycine in a Gly-Xaa-Yaa triplet by another amino acid. We delineated a Y-position substitution in a small pedigree with a combined OI/Ehlers-Danlos Syndrome (EDS) phenotype, characterized by moderately decreased DEXA z-score (-1.3 to -2.6), long bone fractures, and large-joint hyperextensibility. Affected individuals have an alpha1(I)R888C (p.R1066C) substitution in one COL1A1 allele. Polyacrylamide gel electrophoresis (PAGE) of [(3)H]-proline labeled steady-state Collagen reveals slight overmodification of the alpha1(I) monomer band, much less than expected for a substitution of a neighboring glycine residue, and a faint alpha1(I) dimer. Dimers form in about 10% of proband type I Collagen. Dimer formation is inefficient compared to a possible 25%, probably because the SH-side chains have less proximity in this Y-position than when substituting for a glycine. Theoretical stability calculations, differential scanning calorimetry (DSC) thermograms, and thermal denaturation curves showed only weak local destabilization from the Y-position substitution in one or two chains of a Collagen Helix, but greater destabilization is seen in Collagen containing dimers. Y-position Collagen dimers cause kinking of the Helix, resulting in a register shift that is propagated the full length of the Helix and causes resistance to proCollagen processing by N-proteinase. Collagen containing the Y-position substitution is incorporated into matrix deposited in culture, including immaturely and maturely cross-linked fractions. In vivo, proband dermal fibrils have decreased density and increased diameter compared to controls, with occasional aggregate formation. This report on Y-position substitutions in type I Collagen extends the range of phenotypes caused by nonglycine substitutions and shows that, similar to X- and Y-position substitutions in types II and III Collagen, the phenotypes resulting from nonglycine substitutions in type I Collagen are distinct from those caused by glycine substitutions.
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Y-position Collagen II mutation disrupts cartilage formation and skeletal development in a transgenic mouse model of spondyloepiphyseal dysplasia.
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2002Co-Authors: Kelly G. Gaiser, B. Kerry Maddox, James G. Bann, Bruce A. Boswell, Douglas R. Keene, Silvio Garofalo, William A. HortonAbstract:Mice were generated by pronuclear injection of a type II Collagen transgene harboring an Arg789Cys (R789C) mutation that has been found in patients with spondyloepiphyseal dysplasia (SED). Expression was directed to cartilage by the murine Col2a1 promoter to examine the consequences of mutations involving the Y-position of the Collagen Helix Gly-X-Y triplet on skeletogenesis. The transgenic mice had very short limbs, short trunk, short snout, and cleft palate; they died at birth. Their growth plates were disorganized and Collagen fibrils were sparse in cartilage matrix. When the transgene was expressed in RCS cells, there was no evidence that R789C-bearing Collagen chains were incorporated into stable Collagen molecules. Molecular modeling of the mutation raised the possibility that it destabilizes the Collagen triple Helix. Together our results suggest that Y-position mutations, such as R789C, can act in a dominant negative manner to destabilize Collagen molecules during assembly, reducing their availability to form fibrils, the deficiency of which profoundly disturbs the template functions of cartilage during skeletogenesis.
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Identification and partial purification of a large, variant form of type XII Collagen.
The Journal of biological chemistry, 1992Co-Authors: Gregory P. Lunstrum, Douglas R. Keene, A M Mcdonough, M P Marinkovich, Nicholas P. Morris, Robert E. BurgesonAbstract:Abstract A large, alternate form of type XII Collagen has been identified in cultures of the human epidermoid cell line WISH. This form, designated XIIA, is comprised of alpha chains that are approximately 90 kDa larger than the 220-kDa alpha chain previously characterized in extracts of fetal chicken and bovine tissues. Results from both Collagenase digestion and rotary shadow analysis of partially purified material show that the increase is due to a larger NC3 domain. While both the large (XIIA) and the small (XIIB) forms of type XII Collagen are identified in pulse-chase radiolabeling of fetal bovine skin explant culture, they are not related in a precursor-product fashion. Inhibition studies with alpha, alpha'-dipyridyl indicate that proper folding of the Collagen Helix is required for complete assembly and secretion of type XIIA in WISH cell culture. The 310-kDa alpha 1A chain is likely to represent the bovine equivalent of a second translation product, estimated to be 340 kDa, predicted from analysis of one complete chick cDNA sequence. Additionally, the amino-terminal amino acid sequence of the 220-kDa bovine alpha 1B chain was determined. This sequence is very near a potential alternate splice site predicted from analysis of chicken type XII cDNA.
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Two type XII-like Collagens localize to the surface of banded Collagen fibrils.
The Journal of cell biology, 1991Co-Authors: Douglas R. Keene, Gregory P. Lunstrum, Nicholas P. Morris, Donald W. Stoddard, Robert E. BurgesonAbstract:Two recently identified Collagen molecules, termed twelve-like A and twelve-like B (TL-A and TL-B) have properties similar to type XII Collagen. These molecules have been localized in human and calf tissues by immunoelectron microscopy. The observations strongly suggest that both molecules are located along the surface of banded Collagen fibers. The epitopes recognized by the antibodies are contained in large, nontriple-helical domains at one end of the Collagen Helix. The epitopes are visualized at a distance from the surface of the banded fibers roughly equal to the length of the nonhelical domains, suggesting that the nonhelical domains extend from the fibril, while the triple-helical domains are likely to bind directly to the fibril surface. Occasionally, both TL-A and TL-B demonstrate periodic distribution along the fibril surface. The period corresponds to the primary interband distance of the banded fibrils. Not all fibrils in a fiber bundle are labeled, nor is the labeling continuous along the length of labeled fibrils. Simultaneous labeling of TL-A and type VI Collagen only rarely shows colocalization, suggesting that TL-A and TL-B do not mediate interactions between the type VI Collagen beaded filaments and banded Collagen fibrils. Also, interfibrillar distances are approximately equivalent in the presence and absence of these type XII-like molecules. While the results do not directly indicate a specific function for these molecules, the localization at the fibril surface suggests that they mediate interactions between the fibrils and other matrix macromolecules or with cells.
Hans Peter Bächinger - One of the best experts on this subject based on the ideXlab platform.
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Vascular Ehlers-Danlos Syndrome Mutations in Type III Collagen Differently Stall the Triple Helical Folding
The Journal of biological chemistry, 2013Co-Authors: Kazunori Mizuno, Sergei P. Boudko, Juergen Engel, Hans Peter BächingerAbstract:Vascular Ehlers-Danlos syndrome (EDS) type IV is the most severe form of EDS. In many cases the disease is caused by a point mutation of Gly in type III Collagen. A slower folding of the Collagen Helix is a potential cause for over-modifications. However, little is known about the rate of folding of type III Collagen in patients with EDS. To understand the molecular mechanism of the effect of mutations, a system was developed for bacterial production of homotrimeric model polypeptides. The C-terminal quarter, 252 residues, of the natural human type III Collagen was attached to (GPP)7 with the type XIX Collagen trimerization domain (NC2). The natural Collagen domain forms a triple helical structure without 4-hydroxylation of proline at a low temperature. At 33 °C, the natural Collagenous part is denatured, but the C-terminal (GPP)7-NC2 remains intact. Switching to a low temperature triggers the folding of the type III Collagen domain in a zipper-like fashion that resembles the natural process. We used this system for the two known EDS mutations (Gly-to-Val) in the middle at Gly-910 and at the C terminus at Gly-1018. In addition, wild-type and Gly-to-Ala mutants were made. The mutations significantly slow down the overall rate of triple Helix formation. The effect of the Gly-to-Val mutation is much more severe compared with Gly-to-Ala. This is the first report on the folding of Collagen with EDS mutations, which demonstrates local delays in the triple Helix propagation around the mutated residue.
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Crystal structure of (Gly-Pro-Hyp)(9) : implications for the Collagen molecular model.
Biopolymers, 2012Co-Authors: Kenji Okuyama, Kazunori Mizuno, Keita Miyama, Hans Peter BächingerAbstract:Collagens have long been believed to adopt a triple-stranded molecular structure with a 10/3 symmetry (ten triplet units in three turns) and an axial repeat of 29 A. This belief even persisted after an alternative structure with a 7/2 symmetry (seven triplet units in two turns) with an axial repeat of 20 A had been proposed. The uncertainty regarding the helical symmetry of Collagens is attributed to inadequate X-ray fiber diffraction data. Therefore, for better understanding of the Collagen Helix, single-crystal analyses of peptides with simplified characteristic amino acid sequences and similar compositions to Collagens have long been awaited. Here we report the crystal structure of (Gly-Pro-Hyp)(9) peptide at a resolution of 1.45 A. The repeating unit of this peptide, Gly-Pro-Hyp, is the most typical sequence present in Collagens, and it has been used as a basic repeating unit in fiber diffraction analyses of Collagen. The (Gly-Pro-Hyp)(9) peptide adopts a triple-stranded structure with an average helical symmetry close to the ideal 7/2 helical model for Collagen. This observation strongly suggests that the average molecular structure of Collagen is not the accepted Rich and Crick 10/3 helical model but is a 7/2 helical conformation.
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High-resolution structures of Collagen-like peptides [(Pro-Pro-Gly)(4)-Xaa-Yaa-Gly-(Pro-Pro-Gly)(4)]: Implications for triple-Helix hydration and Hyp(X) puckering.
Biopolymers, 2009Co-Authors: Kenji Okuyama, Kazunori Mizuno, Chizuru Hongo, Keiichi Noguchi, Shutoku Ebisuzaki, Yuji Tanaka, Norikazu Nishino, Hans Peter BächingerAbstract:Structures of (Pro-Pro-Gly)4-Xaa-Yaa-Gly-(Pro-Pro-Gly)4 (ppg9-XYG) where (Xaa, Yaa) = (Pro, Hyp), (Hyp, Pro) or (Hyp, Hyp) were analyzed at high resolution using synchrotron radiation. Molecular and crystal structures of these peptides are very similar to those of the (Pro-Pro-Gly)9 peptide. The results obtained in this study, together with those obtained from related compounds, indicated the puckering propensity of the Hyp in the X position: (1) Hyp(X) residues involved in the Hyp(X):Pro(Y) stacking pairs prefer the down-puckering conformation, as in ppg9-OPG, and ppg9-OOG; (2) Hyp(X) residues involved in the Hyp(X):Hyp(Y) stacking pairs prefer the up-puckering conformation if there is no specific reason to adopt the down-puckering conformation. Water molecules in these peptide crystals are classified into two groups, the 1st and 2nd hydration waters. Water molecules in the 1st hydration group have direct hydrogen bonds with peptide oxygen atoms, whereas those in the 2nd hydration group do not. Compared with globular proteins, the number of water molecules in the 2nd hydration shell of the ppg9-XYG peptides is very large, likely due to the unique rod-like molecular structure of Collagen model peptides. In the Collagen Helix, the amino acid residues in the X and Y positions must protrude outside of the triple Helix, which forces even the hydrophobic side chains, such as Pro, to be exposed to the surrounding water molecules. Therefore, most of the waters in the 2nd hydration shell are covering hydrophobic Pro side chains by forming clathrate structures. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 361–372, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com