TEKTIP1 and Reduced sperm motility: Collectively, our study reveals the physiological role and potential molecular mechanism of TEKTIP1 in axonemal structure and sperm motility, highlights the importance of MIPs in stabilizing DMTs, and suggests a potential relevance of TEKTIP1 deficiency to human asthenospermia. Tektip1−/− mice will be an excellent animal model to study the DMT organization of sperm flagella using cryo-EM in future.