Hansen, Rosa Rebecca Erritzøe4; Otsu, Mieko5; Braakman, Ineke5; Winther, Jakob R.6
1 Cell Biology and Physiology, Department of Biology, Faculty of Science, Københavns Universitet2 Biomolecular Sciences, Department of Biology, Faculty of Science, Københavns Universitet3 Utrecht University4 Cell Biology and Physiology, Department of Biology, Faculty of Science, Københavns Universitet5 Utrecht University6 Biomolecular Sciences, Department of Biology, Faculty of Science, Københavns Universitet
Plasma cells produce and secrete massive amounts of disulfide-containing antibodies. To accommodate this load on the secretory machinery, the differentiation of resting B cells into antibody-secreting plasma cells is accompanied by a preferential expansion of the secretory compartments of the cells and by an up-regulation of enzymes involved in redox regulation and protein folding. We have quantified the absolute levels of protein thiols, protein disulfides, and glutathionylated proteins in whole cells. The results show that while the global thiol-disulfide state is affected to some extent by the differentiation, steady-state levels of glutathionylated protein thiols are less than 0.3% of the total protein cysteines, even in fully differentiated cells, and the overall protein redox state is not affected until late in differentiation, when large-scale IgM production is ongoing. A general expansion of the ER does not affect global protein redox status until an extensive production of cargo proteins has started.
International Journal of Cell Biology, 2013, Vol 2013