BRSK1 is a brain-specific serine/threonine kinase that functions as a multifaceted regulator of neuronal development and cellular stress responses. In neurons, BRSK1 acts downstream of LKB1 to regulate neuronal polarization by phosphorylating microtubule-associated proteins including tau/MAPT and controlling WEE1 activity 1. BRSK1 also localizes to synaptic vesicles and lipid rafts where enhanced kinase activity supports neurotransmitter release 1. Beyond neuronal functions, BRSK1 participates in DNA damage checkpoints by inhibiting CDK1 through WEE1 activation and CDC25 inhibition. Disease relevance spans reproductive, neurological, and malignant contexts. A BRSK1 variant (rs12611091) associates with premature ovarian failure susceptibility 2, and another variant (rs11668344) confers 2.5-fold increased risk of alkylating chemotherapy-induced reduced ovarian function in childhood cancer survivors 3. Haploinsufficiency of BRSK1 causes epilepsy and neurodevelopmental disorders through dysregulation of axonal development and synaptic function pathways 4. In cancer, BRSK1 exhibits context-dependent roles: it functions as a tumor suppressor in breast cancer by regulating the PI3K/Akt pathway and p27 degradation 5, and frameshift mutations occur in microsatellite-instable gastric and colorectal cancers 6. Conversely, BRSK1 promotes cisplatin resistance in cervical cancer via mitochondrial respiration regulation 7 and activates YAP/TAZ in triple-negative breast cancer 8.