Required for renal tubular integrity. May regulate local cytoskeletal structure in kidney tubule epithelial cells. May regulate ciliary biogenesis through targeting of proteins to the cilia. Plays a role in organogenesis and is involved in the regulation of the Hippo signaling pathway. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with PKD2; may regulate PKD2 targeting to the cilium (PubMed:18235101). Component of a complex containing at least ANKS6, INVS, NEK8 and NPHP3 (By similarity). ANKS6 may organize complex assembly by linking INVS and NPHP3 to NEK8 and INVS may target the complex to the proximal ciliary axoneme (By similarity). Interacts with ANKS3 (PubMed:25671767). Predominantly cytoplasmic. Localizes to the proximal region of the primary cilium and is not observed in dividing cells. Kidney, liver, and testis. Defects in Nek8 are the cause of autosomal recessive juvenile polycystic kidney disease (ARJPKD). Belongs to the protein kinase superfamily. NEK Ser/Thr protein kinase family. NIMA subfamily.