Disitamab vedotin binds HER2 on tumor cells, is internalized, and releases MMAE, which binds tubulin and disrupts microtubules causing mitotic arrest and apoptosis. Tubulin beta is the payload’s intracellular target, not the recognition antigen, so cells aren’t killed because they express tubulin per se; killing occurs in HER2-targeted (and bystander) cells after payload release.