What is endosomal vesicle?
Endosomes are membrane-bound vesicles, formed via a complex family of processes collectively known as endocytosis, and found in the cytoplasm of virtually every animal cell. The basic mechanism of endocytosis is the reverse of what occurs during exocytosis or cellular secretion.
What does endosomal acidification do?
During the endosomal journey, acidification triggers a conformational change of the virus spike protein hemagglutinin (HA) that results in escape of the viral genome from the endosome into the cytoplasm.
What is the endocytic pathway of infection?
Endocytic entry of viruses occurs in a stepwise manner involving attachment to the cell surface, clustering of receptors, activation of signaling pathways, formation of endocytic vesicles and vacuoles, delivery of viral cargo to endosomal compartments, sorting, and escape into the cytosol.
Which type of endocytosis involves clathrin coated vesicles?
Many cell-surface receptors that bind specific extracellular macromolecules become localized in clathrin-coated pits. As a result, they and their ligands are efficiently internalized in clathrin-coated vesicles, a process called receptor-mediated endocytosis.
What is endosomal pathway?
The endosomal network is a dynamic and interconnected “highway” system that allows for the vectorial trafficking and transfer of cargoes between distinct membrane-bound compartments. The function of the endosomal network is to collect internalized cargoes, sort, and disseminate them to their final destinations [44].
What is endosomal sorting?
Endosomes are a collection of intracellular sorting organelles in eukaryotic cells. Molecules or ligands internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation or can be recycled back to the cell membrane in the endocytic cycle.
What is endosomal escape?
The proton sponge effect is often described as a mechanism to induce endosomal escape. The mechanism proposes that during the acidification of the endosome, polymers with a buffering capacity inhibit the drop in pH, and cause the cell to continue pumping protons into the endosome to reach the desired pH.
What’s the correct order of steps for viral replication?
Viral replication involves six steps: attachment, penetration, uncoating, replication, assembly, and release.
What does invading the host cell enable the virus to do?
In the lytic cycle, the virus attaches to the host cell and injects its DNA. Using the host’s cellular metabolism, the viral DNA begins to replicate and form proteins.
What is the process of receptor-mediated endocytosis?
Receptor-mediated endocytosis (RME), also called clathrin-mediated endocytosis, is a process by which cells absorb metabolites, hormones, proteins – and in some cases viruses – by the inward budding of the plasma membrane (invagination). Only the receptor-specific substances can enter the cell through this process.
Which process results in the formation of clathrin-coated vesicles?
Clathrin-coated vesicles are initiated by the accumulation of adaptor and accessory proteins that bind receptors on the plasma membrane to subsequently drive the nucleation of clathrin [41]. One role of these adaptors is to induce membrane curvature, thereby leading to membrane invagination and vesicle formation.
What is endosomal pH?
Compared to a cytoplasmic pH (of about 7.0), the endosomal and lysosomal lumen pH is maintained in a range of 6.5 to 4.5, due to the activity of the ATP-dependent proton pumps present in the membrane of both endosomes and lysosomes [7].