Human STT3A knockout HEK-293T cell lysate

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

STT3A also known as oligosaccharyltransferase 48 kDa subunit plays an important role in the enzymatic process of N-glycosylation specifically as a catalytic subunit in the oligosaccharyltransferase (OST) complex. This protein has a mass of approximately 48 kDa. STT3A is expressed predominantly in rough endoplasmic reticulum membranes where it contributes to the transfer of oligosaccharides onto nascent polypeptide chains a critical step for protein maturation and function.

Biological function summary

STT3A is part of the OST complex which catalyzes the transfer of glycan from a lipid donor to asparagine residues on nascent polypeptides in a process known as co-translational N-glycosylation. This modification is essential for proper protein folding stability and activity. The OST complex with STT3A as a catalytic core is fundamental in eukaryotic cells affecting the function of numerous glycoproteins. It interacts with various components within the endoplasmic reticulum to ensure efficient glycosylation.

Pathways

The involvement of STT3A extends to the protein processing in endoplasmic reticulum pathway and is integral to the broader process of protein folding and quality control. This pathway ensures proper protein configuration and prevents the accumulation of misfolded proteins. STT3A functionally relates to proteins like calnexin and calreticulin which work in the calnexin/calreticulin cycle to assist in the folding of glycoproteins indicating its important role in maintaining protein homeostasis in cells.

Associated diseases and disorders

Defects or dysregulation of STT3A have associations with congenital disorders of glycosylation (CDG) a group of rare inherited metabolic disorders affecting glycoprotein synthesis. Anomalies in STT3A activity can disrupt normal glycoprotein functions leading to a wide range of symptoms including developmental delays and neurological issues. Moreover STT3A dysfunction has connections with cancer progression as altered N-glycosylation patterns are frequently observed in tumor cells affecting proteins such as EGFR and HER2 which are often targets in oncogenesis.