Phomopsins are a family of mycotoxins produced by the fungus D. toxica, which predominantly infects lupines. Ingestion of lupines infected with D. toxica causes lupinosis, a degenerative disorder that can result in acute liver damage, brain damage, and death. Phomopsin A is a cyclic hexapeptide mycotoxin that binds β-tubulin in a vinca domain, overlapping with the site targeted by vinblastine and other tubulin inhibitors. It binds β-tubulin from higher organisms but not α-tubulin or fungal mycelial tubulin. Phomopsin A blocks microtubule growth, modulates the dynamics of microtubules, and interferes with mitosis.
