In sperm function, IQUB modulates Ca2+/CaM-dependent inhibition of the p-ERK1/2/RSPH3 pathway to support flagellum radial spoke assembly, with mutations (e.g., c.842del, p.L281Pfs*28) causing asthenozoospermia despite normal sperm morphology; IQCN, by contrast, mediates acroplaxome stability and sperm head shaping, and its inactivation leads to acrosomal defects and fertilization failure due to impaired oocyte activation. This evidence concerns the gene IQUB and Reduced sperm motility.