Shiga toxin 2 subunit B (Stx2B)

Shiga toxin 2 subunit B (Stx2B) is the receptor-binding component of the AB5-type Shiga toxin 2, primarily secreted by enterohemorrhagic Escherichia coli (EHEC) such as O157:H7 (UniProt: P09385). The B subunit forms a homopentameric ring that specifically recognizes and binds to the globotriaosylceramide (Gb3) glycolipid on the surface of host endothelial cells, particularly in the kidneys and brain (PubMed: 21835005). Following binding, the toxin-receptor complex is internalized via endocytosis and follows a retrograde transport pathway to the endoplasmic reticulum, where the catalytic A subunit is released into the cytosol to inhibit protein synthesis (PubMed: 11544340). Stx2 is significantly more clinically relevant than Stx1, as it is more strongly associated with the development of hemolytic uremic syndrome (HUS), a life-threatening condition characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure (PubMed: 25139416). As a therapeutic target, Stx2B is the focus of neutralizing monoclonal antibodies, such as Urtoxazumab, and synthetic multivalent inhibitors designed to block the toxin-Gb3 interaction and prevent systemic toxicity (PubMed: 16461015).

Other names

Shiga-like toxin 2 subunit BVerotoxin 2 subunit BStx2BSLT-2BShiga toxin 2B

Neutralization of toxin binding to the host cell receptor globotriaosylceramide (Gb3), preventing cellular entry and subsequent cytotoxicity.