Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xan... more Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xanthomatosis, and premature coronary artery disease. Three loci have been described for this condition (1p35, 15q25-q26 and 13q). Recently, the responsible gene at the 1p35 locus, encoding an LDL receptor adaptor protein (ARH) has been identified. We studied a Mexican ARH family with two affected siblings. Sequence analysis of the ARH gene (1p35 locus) revealed that the affected siblings are homozygous for a novel mutation (IVS4+2T>G) affecting the donor splice site in intron 4, whereas both the parents and an unaffected sister are heterozygous for this mutation. The IVS4+2T>G mutation results in a major alternative transcript derived from a cryptic splice site, which carries an in-frame deletion of 78 nucleotides in the mature mRNA. The translation of this mRNA yields a mutant protein product (ARH-26) lacking 26 amino acids, resulting in the loss of beta-strands beta6 and beta7 from the PTB domain. This is the first case where a naturally occurring mutant with an altered PTB domain has been identified.
β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main tar... more β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main target antigen for antiphospholipid antibodies in patients with antiphospholipid syndrome (APS). β2GPI binds with high affinity to the atherogenic lipoprotein Lp(a) which shares structural homology with plasminogen, a key molecule in the fibrinolytic system. Impaired fibrinolysis has been described in APS. The present work reports the interaction between β2GPI and Glu-Plasminogen which may explain the recently described proteolytic effect of plasmin on β2GPI. In the process of Glu-Plasminogen activation, we found an increase in plasmin generation both at fibrin and cellular surface level as a function of the concentration of β2GPI added, suggesting an important role as a cofactor in the trimolecular complex β2GPI-Plasminogen-tPA. This phenomenon represents a novel regulatory step both in the positive feedback mechanism for extrinsic fibrinolysis and in antithrombotic regulation. IgG anti-β2GPI antibodies recognized the β2GPI at the endothelial surface inducing its activation with an increase of ICAM-I and a decrease in the expression of thrombomodulin favoring a pro-thrombotic state in the vascular endothelium. The interference in the plasmin conversion by anti-β2GPI antibodies could generate thrombosis as observed in APS.
Journal of Molecular Graphics & Modelling, Jan 1, 2007
Flaviviridae non-structural 3 protein (NS3) is a multifunctional enzyme, composed by a protease d... more Flaviviridae non-structural 3 protein (NS3) is a multifunctional enzyme, composed by a protease domain (NS3pro) and an RNA helicase domain (NS3hel). The activities present in NS3 have proved to be critical for viral replication. The replicative cycle of Flaviviridae requires coordinated regulation of all the activities present in the full-length NS3 protein, however, the exact nature of these interactions remains unclear. The present work aimed to determine common structural features between NS3 of dengue and hepatitis C viruses and to characterize residues involved in the regulation of the interdomain motions between NS3pro and NS3hel. Analysis of the root mean square (RMS) variation shows that NS3pro increases the stability of subdomain 1 of the RNA helicase. Moreover, the dynamic behaviour of the carboxy terminus of NS3hel, supports the hypothesis that, upon release of the carboxy-terminus from NS3pro, the residues involved in this interaction are folded back into the last α-helix. Using normal mode analysis, we characterized slow collective motions of NS3, and observed that the two lowest-frequency normal modes are enough to describe reorientations of NS3pro relative to NS3hel. These movements induced an increment in the exposure of the active site of NS3pro that can be important during the proteolytic processing of the viral polyprotein. The third low-frequency normal mode was correlated to subdomain reorientations of NS3hel, similar to those proposed during NTP hydrolysis and dsRNA unwinding. Based on these data, we support a dynamic model, in which the domain movements between NS3pro and NS3hel result in the regulation of its activities.
Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xan... more Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xanthomatosis, and premature coronary artery disease. Three loci have been described for this condition (1p35, 15q25-q26 and 13q). Recently, the responsible gene at the 1p35 locus, encoding an LDL receptor adaptor protein (ARH) has been identified. We studied a Mexican ARH family with two affected siblings. Sequence analysis of the ARH gene (1p35 locus) revealed that the affected siblings are homozygous for a novel mutation (IVS4+2T>G) affecting the donor splice site in intron 4, whereas both the parents and an unaffected sister are heterozygous for this mutation. The IVS4+2T>G mutation results in a major alternative transcript derived from a cryptic splice site, which carries an in-frame deletion of 78 nucleotides in the mature mRNA. The translation of this mRNA yields a mutant protein product (ARH-26) lacking 26 amino acids, resulting in the loss of beta-strands beta6 and beta7 from the PTB domain. This is the first case where a naturally occurring mutant with an altered PTB domain has been identified.
β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main tar... more β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main target antigen for antiphospholipid antibodies in patients with antiphospholipid syndrome (APS). β2GPI binds with high affinity to the atherogenic lipoprotein Lp (a) which shares ...
Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xan... more Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xanthomatosis, and premature coronary artery disease. Three loci have been described for this condition (1p35, 15q25-q26 and 13q). Recently, the responsible gene at the 1p35 locus, encoding an LDL receptor adaptor protein (ARH) has been identified. We studied a Mexican ARH family with two affected siblings. Sequence analysis of the ARH gene (1p35 locus) revealed that the affected siblings are homozygous for a novel mutation (IVS4+2T>G) affecting the donor splice site in intron 4, whereas both the parents and an unaffected sister are heterozygous for this mutation. The IVS4+2T>G mutation results in a major alternative transcript derived from a cryptic splice site, which carries an in-frame deletion of 78 nucleotides in the mature mRNA. The translation of this mRNA yields a mutant protein product (ARH-26) lacking 26 amino acids, resulting in the loss of beta-strands beta6 and beta7 from the PTB domain. This is the first case where a naturally occurring mutant with an altered PTB domain has been identified.
β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main tar... more β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main target antigen for antiphospholipid antibodies in patients with antiphospholipid syndrome (APS). β2GPI binds with high affinity to the atherogenic lipoprotein Lp(a) which shares structural homology with plasminogen, a key molecule in the fibrinolytic system. Impaired fibrinolysis has been described in APS. The present work reports the interaction between β2GPI and Glu-Plasminogen which may explain the recently described proteolytic effect of plasmin on β2GPI. In the process of Glu-Plasminogen activation, we found an increase in plasmin generation both at fibrin and cellular surface level as a function of the concentration of β2GPI added, suggesting an important role as a cofactor in the trimolecular complex β2GPI-Plasminogen-tPA. This phenomenon represents a novel regulatory step both in the positive feedback mechanism for extrinsic fibrinolysis and in antithrombotic regulation. IgG anti-β2GPI antibodies recognized the β2GPI at the endothelial surface inducing its activation with an increase of ICAM-I and a decrease in the expression of thrombomodulin favoring a pro-thrombotic state in the vascular endothelium. The interference in the plasmin conversion by anti-β2GPI antibodies could generate thrombosis as observed in APS.
Journal of Molecular Graphics & Modelling, Jan 1, 2007
Flaviviridae non-structural 3 protein (NS3) is a multifunctional enzyme, composed by a protease d... more Flaviviridae non-structural 3 protein (NS3) is a multifunctional enzyme, composed by a protease domain (NS3pro) and an RNA helicase domain (NS3hel). The activities present in NS3 have proved to be critical for viral replication. The replicative cycle of Flaviviridae requires coordinated regulation of all the activities present in the full-length NS3 protein, however, the exact nature of these interactions remains unclear. The present work aimed to determine common structural features between NS3 of dengue and hepatitis C viruses and to characterize residues involved in the regulation of the interdomain motions between NS3pro and NS3hel. Analysis of the root mean square (RMS) variation shows that NS3pro increases the stability of subdomain 1 of the RNA helicase. Moreover, the dynamic behaviour of the carboxy terminus of NS3hel, supports the hypothesis that, upon release of the carboxy-terminus from NS3pro, the residues involved in this interaction are folded back into the last α-helix. Using normal mode analysis, we characterized slow collective motions of NS3, and observed that the two lowest-frequency normal modes are enough to describe reorientations of NS3pro relative to NS3hel. These movements induced an increment in the exposure of the active site of NS3pro that can be important during the proteolytic processing of the viral polyprotein. The third low-frequency normal mode was correlated to subdomain reorientations of NS3hel, similar to those proposed during NTP hydrolysis and dsRNA unwinding. Based on these data, we support a dynamic model, in which the domain movements between NS3pro and NS3hel result in the regulation of its activities.
Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xan... more Autosomal recessive hypercholesterolemia (ARH) is characterized by elevated LDL serum levels, xanthomatosis, and premature coronary artery disease. Three loci have been described for this condition (1p35, 15q25-q26 and 13q). Recently, the responsible gene at the 1p35 locus, encoding an LDL receptor adaptor protein (ARH) has been identified. We studied a Mexican ARH family with two affected siblings. Sequence analysis of the ARH gene (1p35 locus) revealed that the affected siblings are homozygous for a novel mutation (IVS4+2T>G) affecting the donor splice site in intron 4, whereas both the parents and an unaffected sister are heterozygous for this mutation. The IVS4+2T>G mutation results in a major alternative transcript derived from a cryptic splice site, which carries an in-frame deletion of 78 nucleotides in the mature mRNA. The translation of this mRNA yields a mutant protein product (ARH-26) lacking 26 amino acids, resulting in the loss of beta-strands beta6 and beta7 from the PTB domain. This is the first case where a naturally occurring mutant with an altered PTB domain has been identified.
β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main tar... more β2-glycoprotein I (β2GPI) is a glycoprotein of unknown physiological function. It is the main target antigen for antiphospholipid antibodies in patients with antiphospholipid syndrome (APS). β2GPI binds with high affinity to the atherogenic lipoprotein Lp (a) which shares ...
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Papers by Luis Rosales