CSNK1E encodes casein kinase 1 epsilon, a serine/threonine kinase with critical roles in circadian rhythm regulation and cellular signaling pathways. As a central component of the molecular circadian clock, CSNK1E regulates circadian period length by controlling the phosphorylation, nuclear transport, and degradation of PER1 and PER2 proteins 1. The protein participates in Wnt signaling through phosphorylation of DVL1 and DVL2 proteins, and contributes to non-canonical Wnt pathway regulation 2. CSNK1E demonstrates significant disease relevance across multiple conditions. Genetic variants are associated with bipolar disorder susceptibility in Korean populations 3, while elevated expression correlates with poor prognosis in hepatocellular carcinoma and multiple myeloma 45. In multiple myeloma, CSNK1E sustains mitochondrial metabolism by maintaining oxidative phosphorylation gene expression 5. The kinase also contributes to neurodegeneration through TDP-43 phosphorylation in amyotrophic lateral sclerosis models 6. Clinically, CSNK1E represents a promising therapeutic target, with dual CK1δ/CK1ε inhibitors showing efficacy in multiple myeloma treatment and potential neuroprotective effects in ALS models 56.