The function of ENSG00000204659 (CBY3, chibby family member 3) is as follows. Plays a key role in the correct positioning of the annulus, a septin-based ring structure in the sperm flagellum, serving both as a physical barrier and a membrane diffusion barrier that separates the midpiece (MP) from the principal piece (PP) (By similarity). This positioning is essential for proper sperm motility and function (By similarity). CBY3 interacts with CIBAR1 to form a complex which localizes to the curved membrane region of the flagellar pocket (By similarity). By doing so, may provide stability and rigidity to the periannular membrane to prevent membrane deformation (By similarity). This function is crucial for halting annulus migration at the proximal end of the fibrous sheath-containing PP (By similarity). .