Abstract

Different protein degradation pathways exist in cells. However, the bulk of cellular proteins are degraded by the ubiquitinproteasome system (UPS), which is one of these pathways. The upkeep of cellular protein homeostasis is facilitated by the ubiquitin proteasome system, which has a variety of important functions. With the emergence of eukaryotic organisms, the relationship between ubiquitylation and proteolysis by the proteasome became apparent. SARS-COV-2 hijack ubiquitin proteasome system and cause their viral protein to become ubiquitinated, facilitating assembly and budding. Ubiquitination on the E-K38 residue gave the virion the ability to engage with at least one putative cellular receptor, TIM-1, boosting virus entry, reproduction, and pathogenesis. A fraction of infectious viral particles produced during replication have ubiquitinated. The Ubiquitin system promotes viral replication. In order to replicate their viral genome after entering the host cell, viruses combine the resources of the host cell with recently generated viral proteins. Additionally, viruses have the ability to encode deubiquitinating (DUB)-active proteins that can boost viral replication through both direct and indirect means. The SARS-CoV-2 PLpro protein is a DUB enzyme that is necessary for breaking down viral polyproteins in order to create a working replicase complex and promote viral propagation. The ubiquitin-like molecule ISG15, which is likewise a regulator of the innate immune response and has antiviral characteristics, can also be broken down by this enzyme. However, limiting the E1-activating enzyme's ability to suppress the ubiquitination pathway prevented virus infection but did not prevent viral RNA genome translation. Numerous investigations have revealed that the use of proteasome inhibitors has a detrimental effect on the replication of SARS-CoV-2 and other viruses in the host cell. Studies have shown that the use of proteasome inhibitors is also known to deplete free cellular ubiquitin, which may have an impact on viral replication and other vital cellular functions.

Keywords: Ubiquitin proteasome system; SARS-CoV-2; Ubiquitylation