MEMO1 (Mediator of ErbB2-driven cell motility 1) is a 297 amino acid protein. It is thought to relax extracellular chemotactic signals that are targeted at the microtubule cytoskeleton, thereby controlling cell migration. Additionally, MEMO1 is required for breast carcinoma migration, suggesting an important role in tumorigenesis. The MEMO1-RHOA-DIAPH1 signaling pathway plays an important role in ERBB2-dependent stabilization of microtubules at the cell cortex. It controls the localization of APC and CLASP2 to the cell membrane, via the regulation of GSK3B activity.