Shiga toxin type 2 (Stx2)

Shiga toxin type 2 (Stx2) is a potent exotoxin produced primarily by certain pathogenic strains of *Escherichia coli* (notably O157:H7) and is a key virulence factor in severe human disease such as hemorrhagic colitis and hemolytic uremic syndrome. Stx2 belongs to the family of AB5 toxins, consisting of one catalytically active A subunit surrounded by a pentamer of B subunits. The B subunits specifically bind to the glycolipid receptor globotriaosylceramide (Gb3) on host cells, particularly endothelium in the kidneys and central nervous system. Once internalized, the A1 fragment of the A subunit depurinates a specific adenine from the sarcin–ricin loop of the 28S rRNA, irreversibly inhibiting protein synthesis and leading to cell death[1][2][3][4][5][6][7]. Stx2 is structurally and functionally distinct from Stx1, being significantly more potent and more strongly associated with risk of severe renal and neurological complications in humans[2][5][6]. There are currently no approved therapeutic inhibitors; treatment is supportive. The biotoxin’s mode of action and exquisite potency, combined with a lack of effective neutralizing agents, pose major clinical and public health challenges[7][5].

Other names

Shiga-like toxin IIVerotoxin 2Stx2Shiga toxin 2Shiga-like toxin type 2

Ribosome inactivation by depurination of 28S rRNA, Inhibition of protein synthesis, Induction of apoptosis