Plays a critical role in regulating mitochondrial ultrastructure and function by maintaining the integrity of mitochondrial morphology, particularly the organization of cristae (PubMed:30404948). Preferentially binds to negatively charged phospholipids like cardiolipin and phosphatidylinositol 4,5- bisphosphate enhancing its interaction with mitochondrial membranes (PubMed:30404948). Induces membrane curvature and tubulation, which are critical for maintaining mitochondrial ultrastructure and the organization of cristae (PubMed:30404948). Plays a crucial role in ciliogenesis (PubMed:27528616, PubMed:30395363). May play a role in limb development through its role in ciliogenesis (PubMed:30395363). 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). Interacts with CBY3 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). {ECO:0000250|UniProtKB:Q8BP22, ECO:0000269|PubMed:27528616, ECO:0000269|PubMed:30395363, ECO:0000269|PubMed:30404948}. This is the function of ENSG00000188343 (CIBAR1, CBY1 interacting BAR domain containing 1).