MAML1 (mastermind like transcriptional coactivator 1) is a multifunctional transcriptional coregulator that serves as a critical coactivator for Notch signaling pathways. MAML1 forms a ternary complex with the intracellular domain of Notch (ICN) and the DNA-binding protein CSL, enhancing Notch-induced transcription of target genes such as HES-1 1. Beyond Notch signaling, MAML1 functions as a coactivator for diverse transcription factors including p53, MEF2C, and β-catenin, and interacts with histone acetyltransferase p300 to increase its activity 2. The protein exhibits global effects on cellular processes, influencing DNA methylation patterns and gene expression across thousands of CpG sites, particularly affecting genes involved in urogenital system development and embryogenesis 3. In disease contexts, MAML1 demonstrates oncogenic properties across multiple cancer types. In hepatocellular carcinoma, YAP-induced MAML1 cooperates with STAT3 to drive tumor progression through p300-dependent STAT3 acetylation 4. MAML1 also promotes triple-negative breast cancer aggressiveness by regulating Notch1 and Gli1 stability through inhibition of the E3 ubiquitin ligase Itch 5. These findings establish MAML1 as both a developmental regulator and potential therapeutic target in cancer.