Toxicity of botulinum toxin type F (botF)

Botulinum toxin type F (botF) is only very rarely associated with human disease (Hatheway 1995) and a pathway by which it might enter the circulation from the human gut has not been described. Nevertheless, the toxin itself, a disulfide-bonded heavy chain (HC) - light chain (LC) heterodimer ("dichain"), is capable of binding to neurons by interactions with cell-surface ganglioside and synaptic vesicle protein 2 (SV2) (Fu et al. 2009; Rummel et al. 2009), the bound toxin can enter synaptic vesicles and release its LC moiety into the cytosol of targeted cells (Montal 2010), and the botF LC can cleave vesicle-associated membrane proteins 1 and 2 (VAMP1 and 2) on the cytosolic face of the synaptic vesicle membrane (Yamasaki et al. 1994). These four events are annotated here.

肉毒杆菌素F型（botF）与人类疾病关联极为罕见（Hatheway，1995年），其从人体肠道进入血液循环的途径尚未被描述。然而，该毒素本身，作为一种二硫键连接的重链（HC）-轻链（LC）异源二聚体（双链），能够通过作用于细胞表面的神经节苷脂和突触囊泡蛋白2（SV2）与神经元结合（Fu等，2009年；Rummel等，2009年），结合的毒素可以进入突触囊泡并释放其LC组分至目标细胞的细胞质中（Montal，2010年），而botF的LC能够切割位于突触囊泡膜细胞质面的囊泡相关膜蛋白1和2（VAMP1和2）（Yamasaki等，1994年）。此处对这四个事件进行了注释。