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Endocytosis is the uptake or internalization of material by a cell, through the formation of a membrane bound vesicle. The process of endocytosis involves the folding of the plasma membrane, creating membrane invaginations containing the particles to be internalized. The plasma membrane surrounds the particles forming a vesicle, which detaches from the plasma membrane and is trafficked to its intracellular destination.
|Cat. No.||Product Name / Activity|
|Potent and selective PIKfyve inhibitor|
|Inhibits receptor-mediated endocytosis; also inhibits apoptosis and autophagy; antimalarial|
|Autophagy inhibitor; also TLR9 inhibitor|
Endocytosis is an evolutionarily conserved process that is essential for cell growth and survival. Endocytosis is important in metabolism, as it mediates the uptake of nutrients, and the process is also crucial in control of cell surface receptor levels, plasma membrane turnover and cell signaling. Endocytosis occiurs in dividing as well as nondividing cells, including quiescent, terminally differentiated, and senescent cells.
Endocytosis is key in the maintenance of exocytosis, the process by which proteins and other substances are released from cells. Vesicular membranes and proteins released by cells during exocytosis are retrieved for recycling by endocytosis. In neurons, inhibition of endocytosis results in depletion of vesicles and abolition of synaptic transmission.
Certain infectious agents, such as bacteria and viruses may exploit endocytosis to enter host cells. The majority of viruses require endocytosis for entry into host cells and replication, and this is being investigated as a potential target for antiviral therapies, including in the treatment of COVID-19. Most bacteria can replicate by themselves, but others highjack the endocytosis process to gain entry into a host cell, where they co-opt the cell's replication machinery.
Receptor-mediated endocytosis (RME; also known as clathrin-mediated endocytosis, CME) is the process of selective uptake of specific macromolecules, including receptors and nutrients. The macromolecules bind to receptors located in clathrin-coated pits in the plasma membrane. Following receptor binding, adaptor proteins in the cell cytoplasm recruit clathrin chains, which polymerize forming invaginations in the plasma membrane. The neck of the invaginated clathrin-coated pits is severed by the GTPase dynamin.
Following internalization, the clathrin-coated vesicles shed their coats and fuse with early endosomes. A feature of early endosomes is that they have an acid internal pH. The endocytosis inhibitor Chloroquine increases the internal pH of early endosomes.
Cells also use clathrin-independent endocytosis pathways; this involves the uptake of molecules into non-clathrin coated membrane pits, known as caveolae. These caveolae are enriched with cholesterol, sphingolipids and the protein caveolin.
Phagocytosis is a form of endocytosis, and is the process by which cells engulf large particles, cell debris or whole cells, including bacteria. Phagocytosis plays a key role in the immune system, where phagocytic cells such as macrophages, polymorphonuclear leukocytes and dendritic cells internalize invading pathogens, including bacteria and viruses, for destruction.
Tocris offers the following scientific literature for Endocytosis to showcase our products. We invite you to request* your copy today!
*Please note that Tocris will only send literature to established scientific business / institute addresses.
GPCRs can interact with multiple distinct transducers or regulatory proteins and these can be preferentially engaged in an agonist-specific manner giving rise to biased agonism. This poster discusses cutting edge GPCR signaling pharmacology and highlights therapeutic applications of biased agonism.