MAST2 is a microtubule-associated serine/threonine kinase that functions as an AGC kinase family member with multiple cellular roles. Its kinase activity is regulated by the mTOR pathway and does not follow the canonical AGC kinase T-loop phospho-activation model; instead, it contains a unique insertion stabilized by ion-pair interactions 1. The DUF1908 domain is necessary for catalytic activity, while the PDZ domain is dispensable 1. MAST2 regulates neurite outgrowth through PDZ domain-mediated protein interactions, with inhibition of MAST2 promoting neuronal development—a property exploited therapeutically by rationally designed peptides 2. At the cellular level, MAST2 influences hemostatic balance in endothelial cells by modulating expression of tissue factor pathway inhibitor (TFPI) and plasminogen activator inhibitor-1 (PAI-1) 3. Clinically, MAST2 dysregulation is associated with cancer, where elevated expression serves as an independent prognostic biomarker in liver cancer with diagnostic capability (AUC 0.925) 4. MAST2 translocations occur in breast and other cancers, frequently representing driver mutations that arise during progression from pre-invasive to invasive disease 5. Rarely, coding variants in MAST2 cause inherited thrombophilia through altered hemostatic gene regulation 3. These findings establish MAST2 as a multifunctional kinase implicated in cancer and thrombotic disorders.