LMTK2 (lemur tyrosine kinase 2) is a transmembrane serine/threonine kinase that regulates diverse cellular processes including endocytic trafficking, protein phosphorylation, and cellular signaling 1. The kinase localizes to endosomal compartments and phosphorylates key substrates including protein phosphatase 1 catalytic subunit (PPP1C), phosphorylase b, and CFTR 1. LMTK2 functions through multiple mechanisms, including modulation of endocytic recycling pathways and interaction with TGF-β1 signaling networks, where knockdown affects expression of thousands of genes involved in cell death, survival, and development 2. The protein's expression is regulated by PKC activation through a TPA-responsive element in its promoter, leading to AP-1-mediated transcriptional upregulation 3. LMTK2 has significant disease relevance, particularly in neurodegeneration where it contributes to disrupted axonal transport, tau hyperphosphorylation, and enhanced apoptosis 4. Rare damaging variants in LMTK2 are associated with Alzheimer's disease risk in Han Chinese populations, with functional studies showing these variants enhance tau phosphorylation and amyloid-β generation 5. Additionally, LMTK2 expression is dramatically reduced in prostate cancer tissues compared to benign tissue, suggesting tumor suppressor functions 6. These findings establish LMTK2 as a critical regulator of cellular homeostasis with therapeutic potential in neurodegenerative diseases and cancer.