Dissecting Structural and Functional Determinants of Microtubules Stabilization through Guided Chemical Modulation.

Paclitaxel (PTX) is a widely used microtubule (MT) stabilizer whose clinical utility is limited by peripheral neuropathy, likely due to drug-induced structural perturbations of neuronal MTs. Here, we aimed to discern how taxane derivatives modify MT lattice architecture and how structural states regulate motor proteins and MAP dynamics. To decouple MT stabilization from adverse structural changes, we designed, synthesized, and characterized several PTX analogues. Our compound 1b retains PTX-like stabilizing activity in vitro and in cells while preserving a native-like MT lattice. This structural separation allowed direct interrogation of MT structure-function relationship in cells. PTX-induced lattice expansion disrupted dynein-mediated retrograde transport, altered kinesin-1 motility and suppressed dynamic Tau exchange. In contrast, 1b preserved more physiological Tau dynamics. These findings reveal that MT stabilization and lattice modulation are separable properties and establish drug-imposed MT states as regulators of intracellular transport and MAP behavior.