Arachidonic acid in the reticuloendothelial network

Overview

Eukaryotic cells have a special pathway that enables communication between various intracellular membrane-bound compartments and also with the extracellular environment. This pathway is termed as the secretory pathway.
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...

Receptor-mediated endocytosis is when bulk amounts of specific molecules are imported into a cell after binding to cell surface receptors. The molecules bound to these receptors are taken into the cell through inward folding of the cell surface membrane, which is eventually pinched off into a vesicle within the cell. Structural proteins, such as clathrin, coat the budding vesicle.
Clathrin-Mediated Endocytosis of LDL
One well-characterized example of receptor-mediated endocytosis is the...

Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...

After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...

Fats and lipids are crucial components in the human body. Some lipid-derived compounds, such as fat-soluble vitamins, eicosanoids, lipoproteins, and glycolipids, also play unique roles to support various  biological processes .
Fat-soluble Vitamins
Fat-soluble vitamins, including vitamins A, D, E, and K, are required in minimal quantities, but their deficiencies can lead to severely abnormal physiological conditions. For example, vitamin A deficiency can cause night blindness, dry skin, delayed...