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Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100

Apolipoprotein (apo) B is an obligatory component of very low density lipoprotein (VLDL), and its cotranslational and posttranslational modifications are important in VLDL synthesis, secretion, and hepatic lipid homeostasis. ApoB100 contains 25 cysteine residues and eight disulfide bonds. Although t...

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Autores principales: Wang, Shiyu, Park, Shuin, Kodali, Vamsi K., Han, Jaeseok, Yip, Theresa, Chen, Zhouji, Davidson, Nicholas O., Kaufman, Randal J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4325832/
https://www.ncbi.nlm.nih.gov/pubmed/25518935
http://dx.doi.org/10.1091/mbc.E14-08-1274
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author Wang, Shiyu
Park, Shuin
Kodali, Vamsi K.
Han, Jaeseok
Yip, Theresa
Chen, Zhouji
Davidson, Nicholas O.
Kaufman, Randal J.
author_facet Wang, Shiyu
Park, Shuin
Kodali, Vamsi K.
Han, Jaeseok
Yip, Theresa
Chen, Zhouji
Davidson, Nicholas O.
Kaufman, Randal J.
author_sort Wang, Shiyu
collection PubMed
description Apolipoprotein (apo) B is an obligatory component of very low density lipoprotein (VLDL), and its cotranslational and posttranslational modifications are important in VLDL synthesis, secretion, and hepatic lipid homeostasis. ApoB100 contains 25 cysteine residues and eight disulfide bonds. Although these disulfide bonds were suggested to be important in maintaining apoB100 function, neither the specific oxidoreductase involved nor the direct role of these disulfide bonds in apoB100-lipidation is known. Here we used RNA knockdown to evaluate both MTP-dependent and -independent roles of PDI1 in apoB100 synthesis and lipidation in McA-RH7777 cells. Pdi1 knockdown did not elicit any discernible detrimental effect under normal, unstressed conditions. However, it decreased apoB100 synthesis with attenuated MTP activity, delayed apoB100 oxidative folding, and reduced apoB100 lipidation, leading to defective VLDL secretion. The oxidative folding–impaired apoB100 was secreted mainly associated with LDL instead of VLDL particles from PDI1-deficient cells, a phenotype that was fully rescued by overexpression of wild-type but not a catalytically inactive PDI1 that fully restored MTP activity. Further, we demonstrate that PDI1 directly interacts with apoB100 via its redox-active CXXC motifs and assists in the oxidative folding of apoB100. Taken together, these findings reveal an unsuspected, yet key role for PDI1 in oxidative folding of apoB100 and VLDL assembly.
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spelling pubmed-43258322015-04-30 Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100 Wang, Shiyu Park, Shuin Kodali, Vamsi K. Han, Jaeseok Yip, Theresa Chen, Zhouji Davidson, Nicholas O. Kaufman, Randal J. Mol Biol Cell Articles Apolipoprotein (apo) B is an obligatory component of very low density lipoprotein (VLDL), and its cotranslational and posttranslational modifications are important in VLDL synthesis, secretion, and hepatic lipid homeostasis. ApoB100 contains 25 cysteine residues and eight disulfide bonds. Although these disulfide bonds were suggested to be important in maintaining apoB100 function, neither the specific oxidoreductase involved nor the direct role of these disulfide bonds in apoB100-lipidation is known. Here we used RNA knockdown to evaluate both MTP-dependent and -independent roles of PDI1 in apoB100 synthesis and lipidation in McA-RH7777 cells. Pdi1 knockdown did not elicit any discernible detrimental effect under normal, unstressed conditions. However, it decreased apoB100 synthesis with attenuated MTP activity, delayed apoB100 oxidative folding, and reduced apoB100 lipidation, leading to defective VLDL secretion. The oxidative folding–impaired apoB100 was secreted mainly associated with LDL instead of VLDL particles from PDI1-deficient cells, a phenotype that was fully rescued by overexpression of wild-type but not a catalytically inactive PDI1 that fully restored MTP activity. Further, we demonstrate that PDI1 directly interacts with apoB100 via its redox-active CXXC motifs and assists in the oxidative folding of apoB100. Taken together, these findings reveal an unsuspected, yet key role for PDI1 in oxidative folding of apoB100 and VLDL assembly. The American Society for Cell Biology 2015-02-15 /pmc/articles/PMC4325832/ /pubmed/25518935 http://dx.doi.org/10.1091/mbc.E14-08-1274 Text en © 2015 Wang et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology.
spellingShingle Articles
Wang, Shiyu
Park, Shuin
Kodali, Vamsi K.
Han, Jaeseok
Yip, Theresa
Chen, Zhouji
Davidson, Nicholas O.
Kaufman, Randal J.
Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100
title Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100
title_full Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100
title_fullStr Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100
title_full_unstemmed Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100
title_short Identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein B100
title_sort identification of protein disulfide isomerase 1 as a key isomerase for disulfide bond formation in apolipoprotein b100
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4325832/
https://www.ncbi.nlm.nih.gov/pubmed/25518935
http://dx.doi.org/10.1091/mbc.E14-08-1274
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