MAP4K (Mitogen-Activated Protein Kinase Kinase Kinase Kinase) is a type of top-level kinase responsible for regulating the MAPK signaling pathway. Family members include HPK1, GLK, GCK, among others, which possess kinase activity domains and participate in cellular stress and immune response processes. MAP4K is expressed in various cells and tissues, localized intracellularly, and activates or inhibits signaling pathways by phosphorylating downstream proteins. Its specific expression and function are particularly important in immune cells such as T cells, regulating immune responses and cell survival. Mutations or changes in expression of MAP4K genes are associated with inflammatory diseases, autoimmune diseases, and cancer.