SAXO1 (stabilizer of axonemal microtubules 1) is a MAP6-related microtubule-stabilizing protein specifically localized to cilia, flagella, and centrioles 1. It functions as the first characterized human member of a conserved family of proteins that stabilize cold-resistant microtubules in these organelles, filling a functional niche previously attributed solely to somatic MAP6 proteins 1. SAXO1 binds to axonemal microtubules through its Mn modules, which are essential for both microtubule stabilization and ciliary localization 1. The protein modulates axoneme length through fine regulation of its localization, indicating critical roles in cilium biogenesis and function 1. In the reproductive context, SAXO1 is expressed in testis tissue 2, and its expression is reduced in asthenozoosperm (sperm with poor motility) 3. Reduced SAXO1 levels correlate with decreased microtubule acetylation and compromised axonemal stability in infertile males, suggesting the protein contributes to sperm motility regulation 3. However, SAXO1 appears individually dispensable for male mouse fertility in knockout studies 2, indicating redundant mechanisms may compensate for its loss. SAXO1 represents a potential therapeutic target for understanding male infertility pathophysiology.