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The cell and tissues
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
There are two distinct types of endoplasmic reticulum. Some of it has ribosomes attached and is known as rough endoplasmic reticulum; this is found in all cells. The other is known as smooth endoplasmic reticulum, as it has no ribosomes attached. It is found in a limited number of cells. The two types of endoplasmic reticulum have different roles.
Functions of the Liver
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The hepatocytes contain a large variety of organelles. The endoplasmic reticulum is a complex of intracellular membranes comprising high-density fatty acid complexes forming a large surface area. The smooth endoplasmic reticulum is associated with drug biotransformation. The rough endoplasmic reticulum is characterized by the presence of aggregates of ribosomes (RNA) on tubules and is responsible for protein synthesis. In addition, peroxisomes are contiguous with both types of endoplasmic reticulum and are sites of β-oxidation of fatty acids and storage of catalase.
Basic Cell Biology
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
The endoplasmic reticulum is an elongated membrane structure and occurs with or without the association of ribosomes; the former is called rough endoplasmic reticulum, whereas the latter is referred to as smooth endoplasmic reticulum. It has been suggested that these structures, at least in the rat liver, participate in the transportation of synthesized protein.
Protective role of PERK-eIF2α-ATF4 pathway in chronic renal failure induced injury of rat hippocampal neurons
Published in International Journal of Neuroscience, 2023
Qi Chen, Jingjing Min, Ming Zhu, Zhanqin Shi, Pingping Chen, Lingyan Ren, Xiaoyi Wang
The endoplasmic reticulum is one of the most important organelles in eukaryotic cells. It is not only the site for protein translation and synthesis as well as calcium ion storage, but also a participant in the transmission and processing of various cell signals. In addition, one of the major functions of the endoplasmic reticulum is to serve as a site for synthesizing secretory and integral membrane proteins.5,6 When cells are stimulated by hypoxia, an imbalance of calcium ions or a change in their concentration occurs in the internal environment, accompanied with the accumulation of some unfolded proteins in the endoplasmic reticulum, resulting in an imbalance between the structure and function of the endoplasmic reticulum. At this time, the corresponding signal pathway is activated to further trigger the endoplasmic reticulum stress (ERS) response.7 Unfolded protein response activation can be triggered in the following three ways: (1) inhibition of protein translation to prevent the production of more folded proteins; (2) induction of the folding of unfolded proteins by the endoplasmic reticulum chaperone; (3) activation of endoplasmic reticulum associated degradation pathways to remove unfolded proteins accumulated in the endoplasmic reticulum.8 However, under prolonged or severe stress, the unfolded protein response initiates programmed cell death.
Gut-derived bacterial flagellin induces beta-cell inflammation and dysfunction
Published in Gut Microbes, 2022
Torsten P.M. Scheithauer, Hilde Herrema, Hongbing Yu, Guido J. Bakker, Maaike Winkelmeijer, Galina Soukhatcheva, Derek Dai, Caixia Ma, Stefan R. Havik, Manon Balvers, Mark Davids, Abraham S. Meijnikman, Ömrüm Aydin, Bert-Jan H. van den Born, Marc G. Besselink, Olivier R. Busch, Maurits de Brauw, Arnold van de Laar, Clara Belzer, Martin Stahl, Willem M. de Vos, Bruce A. Vallance, Max Nieuwdorp, C. Bruce Verchere, Daniël H. van Raalte
Induction of hyperinsulinemia has been shown to promote obesity,4 while prevention of hyperinsulinemia by pancreas-specific genetic knockout of insulin expression prevented obesity, improved insulin sensitivity and did not result in overt hyperglycemia.4 With respect to the pancreatic islets, a chronic demand on beta cells to produce insulin is detrimental. As such, a prolonged increase in insulin secretory rates have been related to endoplasmic reticulum (ER) stress, depletion of intracellular insulin stores and beta-cell apoptosis.41 Pancreatic islets from individuals with T2D have lower insulin content compared to healthy controls.42 In mice, hyperglycemia leads to insulin content loss.43 Reversibly, strategies that induce beta-cell rest are linked to improved beta-cell function over time.44
Induction of caspase-2 gene expression in carboxyl-functionalized carbon nanotube-treated human T-cell leukemia (Jurkat) cell line
Published in Drug and Chemical Toxicology, 2021
Shirin Lotfipanah, Majid Zeinali, Parichehreh Yaghmaei
Caspase-2 exhibits features of both initiator and effector caspases, but its role in apoptosis is controversial and its function as an initiator/effector caspase is still unknown (Fava et al. 2012, Imre et al. 2017). In contrast to conventional initiator caspases-8/9, caspase-2 does not exert enzymatic activation function on effector caspases-3/6/7. It is shown that during pore-forming toxin (PFT)-mediated apoptosis in different cell type, caspase-2 may function as an initiator caspase (Imre et al. 2017). Fava et al. (2012) believe that caspase-2 does not have a direct role in death, neither as an initiator nor as an effector caspase. A damage-sensing function which will be resulted in limited proteolysis for signaling has been suggested for caspase-2 (Fava et al. 2012). Endoplasmic reticulum (ER) stress or some damages to DNA may be resulted in activation of caspase-2 and regulation of cell death.