ULK4 (unc-51-like kinase 4) is a 1,275 amino acid protein that contains one protein kinase domain and one HEAT repeat and belongs to the Ser/Thr protein kinase family. Although containing what is thought to be a catalytically inactive domain, ULK4 may play a role in the ATP-dependent phosphorylation of target proteins. The gene encoding ULK4 maps to human chromosome 3, which houses over 1,100 genes, including a chemokine receptor (CKR) gene cluster and a variety of human cancer-related gene loci.