Nephrocystin-4 (NPHP4)

Nephrocystin-4 is a cilia-associated scaffold protein encoded by the NPHP4 gene. It localizes to the primary cilia, basal bodies, and centrosomes, and is integral to renal tubular development and function. Nephrocystin-4 interacts with nephrocystin (NPHP1), cytoskeletal components (α- and β-tubulin, actin), and adaptor proteins (p130Cas, Pyk2), forming complexes that regulate ciliary structure, signaling, and cell adhesion. As a negative regulator of the Hippo pathway and modulator of Wnt and Sonic hedgehog signaling, it plays a broad role in tissue development and homeostasis. Mutations in NPHP4 result in nephronophthisis type 4 (a pediatric cystic kidney disease often progressing to end-stage renal disease), Senior–Løken syndrome (kidney and retinal involvement), and other ciliopathy phenotypes. No drugs are approved to specifically target nephrocystin-4, and it is not currently considered a therapeutic target in the context of direct drug development. However, NPHP4 mutations serve as an important diagnostic biomarker for genetically defined forms of pediatric nephronophthisis and related syndromes.

Other names

NPHP4nephronophthisis 4 (juvenile) homologKIAA0673SLSN4POC10NephroretininPOC10 centriolar protein homolog (Chlamydomonas)nephrocystin 4