Axoneme-binding protein that plays a role in the regulation of ciliary motility and cilium length. Essential for the assembly of the sperm flagellum and the correct shaping of the sperm head, during spermiogenesis.Contributes in part to flagellar biogenesis by stabilizing QRICH2, promoting the cytoplasmic preassembly of CFAP61 and CFAP91, and regulating the manchette localization of axoneme-associated proteins such as IFT88, DNAI1 and CFAP61. . This is the function of ENSG00000156042 (CFAP70, cilia and flagella associated protein 70).