The two articles I read for this Journal talk about the ACE2 protein and the glycosylation process.
The first article "The glycosylation in SARS-CoV-2 and its receptor ACE2" evaluated the detections, substrates, and biological activities of glycosylation in SARS-CoV-2 proteins as well as the human receptor ACE2, as well as the approved and ongoing SARS-CoV-2 glycosylation therapies. This research paper not only contributes to a better knowledge of viral glycobiology but also the development of new preventive and treatment strategies for SARS-CoV-2 and its variations. It was really interesting and helped me to learn the process of protein glycosylation. In viruses, glycosylation is the most prevalent post-translational modification (PTM). Glycans are covalently attached to the amino acid side chains of proteins through post-translational or co-translational processes, resulting in protein glycosylation. Glycans, which are monosaccharide chains that are either linear or branched, have high solubility and conformational entropy, which controls protein folding, structure, and function. The glycosylation is N-linked and O-linked and this has a big impact on pathogenesis, host recognition, penetration, binding, as well as recycling. Also, the viral protein, for example, Sars-cov-2 itself is heavily reliant on host organelles and enzymes such that the viruses utilize the host cell's metabolic pathway to manufacture their genetic and structural resources.
This picture above helped me understand the N and O linked glycosylation process. That is the N-glycosylation referes to the glycans attached to asparagine (Asn). This process happens in the endoplasmic reticulum where the glycan precursor is generated. Then it is transported to the lumen of the endoplasmic reticulum for the addition of the monosaccharides. And finally three types of N-linked glycans are created such as oligomannose, hybrid, and complex-type.
Citation: Gong, Y., Qin, S., Dai, L., & Tian, Z. (2021, November 15). The glycosylation in SARS-COV-2 and its receptor ACE2. Nature News. Retrieved January 27, 2022, from https://www.nature.com/articles/s41392-021-00809-8
The second article "The role of glycosylation in receptor signaling" also provides various information about the role of glycosylation in protein function, receptor functions, signaling proteins, as well as glycosylation in receptor pharmacology. There was a lot of information that was similar to my first article about the N and O linked glycosylation process. By examining particular instances of how glycosylation regulates receptor signaling in mammalian cells, this research provided an overview of how glycosylation of ligands, receptors, and signaling proteins impacts signal transduction in mammalian cells. As it was discussed in the first article about N-glycosylation and O-glycosylation, this article mentioned that even though these can aid in the proper folding of the final protein product into its three-dimensional, physiologically active structure. This is not true for all glycoproteins. The mechanism for adding these sugar residues is complex and poorly understood, but it is known to involve numerous enzymes and is physiologically regulated. This indicates that glycosylation, as well as other secondary protein processing, is critical for these proteins' biological function.
The picture above helps us understand the regulation of receptor-ligand signaling by the glycosylation.
Citation: Arey, B. J. (2012, September 26). The role of glycosylation in receptor signaling. IntechOpen. Retrieved January 27, 2022, from https://www.intechopen.com/chapters/39461
