1,721,081 research outputs found
Biosynthesis of membrane and secreted e chains during LPS-induced differentiation of an IgE+ murine B lymphoma
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Oxidative protein folding in the secretory pathway and redox-signaling across compartments and cells
No full textThe endoplasmic reticulum (ER) is central for many essential cellular activities, such as folding, assembly and quality control of secretory and membrane proteins, disulfide bond formation, glycosylation, lipid biosynthesis, Ca(2+) storage and signaling. In addition, this multifunctional organelle integrates many adaptive and/or maladaptive signaling cues reporting on metabolism, proteostasis, Ca(2+) and redox homeostasis. We are beginning to understand how these functions and pathways are integrated with one another to regulate homeostasis at cell, tissue and organism levels. The mechanisms underlying the introduction of the proper set of disulfide bonds into secretory proteins (oxidative folding) are strictly related to redox homeostasis, ER stress sensing and signaling and provide a good example of the integration systems operative in the early secretory compartment
Protein quality control in the early secretory pathway
No full textEukaryotic cells are able to discriminate between native and non-native polypeptides, selectively transporting the former to their final destinations. Secretory proteins are scrutinized at the endoplasmic reticulum (ER)–Golgiinterface. Recent findings reveal novel features of the underlying molecular mechanisms, with several chaperone networks cooperating in assisting the maturation of complex proteins and being selectively induced to matchchanging synthetic demands.‘Public’ and ‘private’ chaperones, some of which enriched in specializes subregions, operate for most or selected substrates, respectively. Moreover, sequential checkpoints are distributed along the early secretory pathway, allowing efficiency and fidelity in protein secretion.doi:10.1038/ sj.emboj.760197
The secretory capacity of a cell depends on the efficiency of endoplasmic reticulum-associated degradation
No full textPlasma cells, like other "professional" secretory cells, are capable of secreting thousands of proteins per second. To accomplish this impressive task, they contain a highly developed endoplasmic reticulum (ER), where newly synthesized proteins must fold and assemble to native structures before secretion. Protein biogenesis in the ER is coupled to a tight quality control schedule: aberrant molecules produced upon failure of the folding/oligomerization processes are retained in the ER, and eventually degraded by ER-associated degradation (ERAD) pathways. The activity of the ERAD machinery therefore needs to be adapted to variations in the load of the ER with cargo proteins. If ERAD is insufficient, misfolded proteins accumulate causing ER stress, apoptosis, and ER storage diseases. The capacity of ERAD also critically determines the efficiency of protein secretion. Here we summarize recent findings highlighting the role of ERAD in disease and development, particularly in professional secretory cells
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