Stt3b is one of the catalytically active subunits of the oligosaccharyltransferase (OST) complex. It plays a crucial role in N-glycosylation, a process that modifies proteins by adding sugar molecules. This modification is essential for protein folding, stability, and function, and is involved in multiple biological pathways such as viral replication, immune evasion, and cellular response to toxins [3,4,5]. Genetic models, like gene knockout cells, are valuable for studying Stt3b's functions.

In functional studies, CRISPR-Cas9-mediated knockouts demonstrated that Stt3b is required for α-amanitin toxicity, as its inhibitor indocyanine green (ICG) can act as an antidote [1]. In head and neck squamous cell carcinoma (HNSCC), knockdown of Stt3b suppressed the glycosylation of Epiregulin (EREG), a protein that activates epidermal growth factor receptor (EGFR) and promotes tumor progression, leading to inhibition of PDL1 upregulation and immune evasion [2]. For porcine epidemic diarrhea virus (PEDV), genetic ablation of Stt3b showed that it promotes viral replication by regulating the N-glycosylation of the PEDV S protein [3]. In Lassa virus (LASV) research, knockout of Stt3b caused hypoglycosylation of LASV glycoprotein (GP), indicating its preferential requirement for LASV GP N-glycosylation [4].

In conclusion, Stt3b is essential for N-glycosylation, which impacts various biological processes and disease conditions. Gene knockout models have been instrumental in revealing its role in areas such as toxin response, cancer immune evasion, and viral replication, providing potential targets for therapeutic intervention.