Infertility affects around 8%–12% of couples globally, and in about 50% of these cases, male factors are either the primary cause or contribute significantly to infertility. Any defects during spermiogenesis may result in male subfertility or complete infertility in mammals.1 Previously, we found that CFAP53 is localized in the manchette and sperm tail, and it plays an essential role in sperm flagellum biogenesis. CFAP53 knockout leads to male infertility due to multiple morphological abnormalities of the flagella.2 To investigate the mechanism of CFAP53 during spermiogenesis, we searched for potential CFAP53-interacting proteins and identified a new CFAP53-interacting protein, CCDC178 (Fig. 1A). Western blotting of this protein revealed a significant decrease of CCDC178 in the testes of Cfap53 knockout mice (Fig. S1A–C). We further showed that CCDC178 colocalized with the centrosome marker γ-tubulin and CFAP53 in either HeLa cells or HEK 293T cells (Fig. S1D). Furthermore, we found that CCDC178 is an evolutionarily conserved protein and is predominantly expressed in the testis (Fig. 1B; Fig. S1E–H), suggesting that this protein might also participate in spermiogenesis.