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Genes and Genomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2020
The primary function of the Golgi apparatus is to process and package the macromolecules, such as proteins and lipids, that are synthesized by the cell. It is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the endomembrane system of eukaryotic cells. Vesicles that enter the Golgi apparatus are processed in a cis to trans direction, meaning they coalesce on the cis side of the apparatus and after processing pinch off on the opposite (trans) side to form a new vesicle in the animal cell.
Genes and genomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell. It is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the endomembrane system of eukaryotic cells. Vesicles that enter the Golgi apparatus are processed in a cis to trans direction, meaning they coalesce on the cis side of the apparatus and after processing pinch off on the opposite (trans) side to form a new vesicle in the animal cell.
Identifying Nanotoxicity at the Cellular Level Using Electron Microscopy
Published in Suresh C. Pillai, Yvonne Lang, Toxicity of Nanomaterials, 2019
Kerry Thompson, Alanna Stanley, Emma McDermott, Alexander Black, Peter Dockery
Endocytosis can be roughly divided into two categories, depending on the nature of the internalised substance. Phagocytosis (literally, cell-eating) is the term used to refer to the mechanism by which the cell takes in particulate matter, whereas pinocytosis (literally, cell-drinking) is the term used to describe the intake of fluid. Endocytosis can be performed in one of four ways, depending on the type of cell in question and its functional requirement. The mechanisms are as follows: clathrin-dependent endocytosis, caveolin-mediated endocytosis, macropinocytosis, and dynamin- and clathrin-independent endocytosis (Seto et al., 2002, Liu and Shapiro, 2003). Clathrin-mediated endocytosis, also known as receptor-mediated endocytosis, takes place at specialised regions along the surface of the plasma membrane which are referred to as clathrin-coated pits. This form of endocytosis occurs at a much more rapid rate than that of phagocytosis. The protein clathrin has the ability to generate enclosed regions where the membrane invaginates to form an inward-facing hemisphere which contains the cell surface receptors and material being ingested (Gray, 2008). These enclosures then pinch off from the plasma membrane surface and are carried into the cell for further processing. Vesicles are generally sorted for either degradation by lysosomes or recycling to the plasma membrane. The endocytic system is linked functionally to lysosomal components of the cell (Apodaca, 2001). Lysosomes carry out both heterophagy, breakdown of exogenous contents imported into the cell, and autophagy, which is the breakdown of intracellular components (Dunn et al., 1980). This vesicular pathway is in turn functionally linked with the intracellular membrane system of both the Golgi apparatus and endoplasmic reticulum (Gray, 2008). As previously stated, the properties of the nanoparticle in question can determine the method by which it is internalised. Previous research has investigated whether cells display a preference for shape of particle and many studies corroborate that spherical particles are more readily taken up (Chithrani et al., 2006, Adjei et al., 2014).
Physiological and pathophysiological implications of hydrogen sulfide: a persuasion to change the fate of the dangerous molecule
Published in Journal of the Chinese Advanced Materials Society, 2018
Jan Mohammad Mir, Ram Charitra Maurya
The ER is the primary site of protein synthesis and folding. After being properly folded and disulfide bridged, proteins are trafficked to the Golgi apparatus. During disulfide bond formation, ROS are produced as a result of enzymatic electron transport from thiols to reduce oxygen and produce H2O2.[102] If proteins are misfolded, the unfolded protein response (UPR), which prevents the accumulation of misfolded proteins in the ER, triggers proapoptotic cascades. ER stress and oxidative stress are closely linked. ER stress increases the production of H2S, which sulfhydrates and inhibits protein tyrosine phosphatise (PTP). In turn, PTP inactivates protein kinase-like ER kinase (PERK), which inhibits global translation by phosphorylating elF2α. Thus, H2S regulates ER stress by inhibiting global translation. H2S-induced sulfhydration on cysteine residues of PTP protects the phosphatase from oxidative stress, in a similar manner to NO-induced S nitrosylation of PTP. It is possible that H2S may protect proteins from the highly oxidizing environment of the ER, where protein folding is regulated by redox and large amounts of ROS are produced.