DNAI4 encodes a dynein axonemal intermediate chain essential for assembling the axonemal dynein complex, which powers ciliary and flagellar motility. Based on limited published evidence, DNAI4 functions as an interaction partner within the sperm motility machinery alongside heavy and light chain dyneins 1. The protein localizes to axonemal dynein particles and binds dynein heavy and light chains, supporting axoneme structure and function.