MAML1, also named as KIAA0200 and Mam-1 , belongs to the mastermind family. It acts as a transcriptional coactivator for NOTCH proteins. MAML1 has been shown to amplify NOTCH-induced transcription of HES1. It enhances phosphorylation and proteolytic turnover of the NOTCH intracellular domain in the nucleus through interaction with CDK8. MAML1 binds to CREBBP/CBP which promotes nucleosome acetylation at NOTCH enhancers and activates transcription.