Fig. 9.

Proposed mechanism for the roles of the redox environment and mechanism-based inhibitor MI2321 on NQO1 structure and binding to microtubules. Reduced pyridine nucleotides regulate the redox conformation of NQO1 and its binding to microtubules. Inactivation of NQO1 by the indolequinone (IQ) component of the mechanism-based inhibitor MI2321 alters the conformation of NQO1, resulting in decreased binding of NQO1 to microtubules. Lower levels of NQO1 bound to microtubules result in either increased acetylation or decreased deacetylation of lysine⁴⁰ of α-tubulin in the lumen of the microtubule.