A western blotting assay using 16 semen samples (including 8 asthenospermia and 8 normal samples) revealed similar results, indicating COPS7A was significantly upregulated in patients with asthenozoospermia, but CUL3, KLHL7 and NEDD4 were significantly downregulated compared with normal samples (Fig. 9B and Additional file 1: Fig. S3). Here, CUL3 is linked to Reduced sperm motility.