Mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) – also known as hepatocyte progenitor kinase-like/germinal center kinase-like kinase (HGK) and Nck-interacting kinase (NIK) – is an enzyme, specifically a serine/threonine (S/T) kinase encoded by the MAP4K4 gene in humans. MAP4K4 is involved in a wide array of physiological processes including cell migration, proliferation and adhesion; its activity has been implicated in systemic inflammation, metabolic disorders, cardiovascular disease and cancer.