Inoue et al. demonstrate that the microtubule- and actin-binding protein MAP1B promotes invadopodia stabilization, invasion, and tumorigenesis in triple-negative breast cancer cells by preventing autophagic degradation of the pro-invasive protein Tks5 and propose the MAP1B–Tks5–cortactin axis as a potential therapeutic target for TNBC. The gene discussed is MAP1B; the disease is triple-negative breast carcinoma.