Search results for " Reti"
showing 10 items of 868 documents
Out for a Walk Along the Secretory Pathway During Programmed Cell Death
2015
This chapter provides a comprehensive updated analysis on the role of the secretory pathway in the orchestration of cell’s demise, an emerging and promising research topic in the field of plant programmed cell death (PCD). Since my first review on this topic, a plethora of data has been published supporting the concept that endomembrane system-forming subcellular compartments cooperate to coordinate cellular responses to developmental and environmental cues and thereby can dictate a cell’s ultimate fate. Thus, the early secretory pathway, encompassing the endoplasmic reticulum and Golgi apparatus, can be involved in the perception of extrinsic and intrinsic stimuli. It can also be an active…
ROS-Dependent ER Stress and Autophagy Mediate the Anti-Tumor Effects of Tributyltin (IV) Ferulate in Colon Cancer Cells
2020
Organotin compounds represent potential cancer therapeutics due to their pro-apoptotic action. We recently synthesized the novel organotin ferulic acid derivative tributyltin (IV) ferulate (TBT-F) and demonstrated that it displays anti-tumor properties in colon cancer cells related with autophagic cell death. The purpose of the present study was to elucidate the mechanism of TBT-F action in colon cancer cells. We specifically show that TBT-F-dependent autophagy is determined by a rapid generation of reactive oxygen species (ROS) and correlated with endoplasmic reticulum (ER) stress. TBT-F evoked nuclear factor erythroid-2 related factor 2 (Nrf2)-mediated antioxidant response and Nrf2 silenc…
Bax inhibitor-1 is likely a pH-sensitive calcium leak channel, not a H+/Ca2+ exchanger.
2014
The endoplasmic reticulum (ER) plays a key role in the synthesis, folding, and sorting of proteins, and disturbances of this delicate system can cause cell death. The ER also serves as the major intracellular calcium (Ca(2+)) store, and release of Ca(2+) from this store controls diverse cellular functions. At the interface of both these functions of the ER is Bax inhibitor-1 (BI-1), an evolutionarily conserved multifunctional protein that mediates Ca(2+) efflux from the ER and protects against ER stress. Several mechanisms have been proposed to explain how BI-1 might mediate Ca(2+) efflux from the ER. Chang et al. present structural evidence that a bacterial homolog of BI-1, BsYetJ, is a pH…
Coupling Endoplasmic Reticulum Stress to the Cell Death Program
2002
Accumulation of misfolded proteins and alterations in Ca2+ homeostasis in the endoplasmic reticulum (ER) causes ER stress and leads to cell death. However, the signal-transducing events that connect ER stress to cell death pathways are incompletely understood. To discern the pathway by which ER stress-induced cell death proceeds, we performed studies on Apaf-1−/− (null) fibroblasts that are known to be relatively resistant to apoptotic insults that induce the intrinsic apoptotic pathway. While these cells were resistant to cell death initiated by proapoptotic stimuli such as tamoxifen, they were susceptible to apoptosis induced by thapsigargin and brefeldin-A, both of which induce ER stress…
Highlighting Curcumin-Induced Crosstalk between Autophagy and Apoptosis as Supported by Its Specific Subcellular Localization
2020
Curcumin, a major active component of turmeric (Curcuma longa, L.), is known to have various effects on both healthy and cancerous tissues. In vitro studies suggest that curcumin inhibits cancer cell growth by activating apoptosis, but the mechanism underlying the anticancer effect of curcumin is still unclear. Since there is a recent consensus about endoplasmic reticulum (ER) stress being involved in the cytotoxicity of natural compounds, we have investigated using Image flow cytometry the mechanistic aspects of curcumin&rsquo
Studies on the fat body of oncopeltus fasciatus invaded by pseudomonas aeruginosa1
1977
A fatal disease in laboratory cultures of Oncopeltus fasciatus is caused by Pseudomonas aeruginosa , which invades the fat body and destroys it. The cellular breakdown was studied by electron microscopy. Infected fat body tissue shrinks, disintegrates, and dissolves. The nuclei, apparently, remain intact until immediately before cell death. Bacteria, which are found singularly in cytoplasm, form an expanding electron-lucent halo. Within this halo, free ribosomes and ribosomes of rough endoplasmic reticulum (ER) disappear. The changes are presumably caused by proteolytic activity of the parasite, which results in the destruction of the fat body and death of the host. Lipid droplets dissolve,…
Assessment of Endoplasmic Reticulum Stress and the Unfolded Protein Response in Endothelial Cells
2011
In the vascular wall, the most inner cell layer that separates the blood from organelles is comprised of only a single layer of endothelial cells (ECs). This cell type is fundamental to a large variety of processes, ranging from blood coagulation and interaction with inflammatory cells to cardiovascular diseases such as hypertension, diabetes, and atherosclerosis. Dysfunction of ECs is often causally linked to these processes such that research exploring such events attracted much attention. Damage of ECs and subsequent disruption of the intact endothelial barrier can result not only from oxidative stress, but also from conditions that stress the endoplasmic reticulum (ER) and induce a sign…
The N-glycan processing in HT-29 cells is a function of their state of enterocytic differentiation. Evidence for an atypical traffic associated with …
1991
International audience; When the human colon cancer cells HT-29 undergo enterocytic differentiation, they correctly process their N-glycans, whereas their undifferentiated counterpart are unable to process Man9-8-GlcNAc2 species, the natural substrate of alpha-mannosidase I. As this enzyme is fully active in both HT-29 cell populations, we hypothesize that N-glycoproteins are unable to reach the cis Golgi, the site where alpha-mannosidase I has been localized. We have demonstrated this point by using 1-deoxymannojirimycin, leupeptin, and monensin. In the presence of 1-deoxymannojirimycin, a specific inhibitor of alpha-mannosidase I, differentiated HT-29 cells, as expected, accumulate Man9-8…
Characterizing the N-terminal processing motif of MHC class I ligands.
2008
Abstract Most peptide ligands presented by MHC class I molecules are the product of an intracellular pathway comprising protein breakdown in the cytosol, transport into the endoplasmic reticulum, and successive N-terminal trimming events. The efficiency of each of these processes depends on the amino acid sequence of the presented ligand and its precursors. Thus, relating the amino acid composition N-terminal of presented ligands to the sequence specificity of processes in the pathway gives insight into the usage of ligand precursors in vivo. Examining the amino acid composition upstream the true N terminus of MHC class I ligands, we demonstrate the existence of a distinct N-terminal proces…
Folding and insertion of transmembrane helices at the ER
2021
In eukaryotic cells, the endoplasmic reticulum (ER) is the entry point for newly synthesized proteins that are subsequently distributed to organelles of the endomembrane system. Some of these proteins are completely translocated into the lumen of the ER while others integrate stretches of amino acids into the greasy 30 Å wide interior of the ER membrane bilayer. It is generally accepted that to exist in this non-aqueous environment the majority of membrane integrated amino acids are primarily non-polar/hydrophobic and adopt an α-helical conformation. These stretches are typically around 20 amino acids long and are known as transmembrane (TM) helices. In this review, we will consider how tra…