FBF1 (Fas binding factor 1) is a multifunctional protein primarily known as a transition fiber component essential for primary cilium organization and function. At the ciliary base, FBF1 localizes to distal appendages where it regulates cilia gating in coordination with TALPID3 and ANKRD26 1. FBF1 plays distinct roles in ciliary dynamics: it is specifically required for ciliary disassembly rather than assembly 2, and regulates intraflagellar transport and preciliary vesicle recruitment as part of a hierarchical protein assembly pathway 3. Beyond ciliary function, FBF1 has emerged as a critical senescence regulator. Under cellular stress, FBF1 undergoes SUMOylation at the ciliary base following downregulation of ciliary ARL GTPases, then translocates to promyelocytic leukemia nuclear bodies (PML-NBs) to initiate senescence responses 4. This translocation occurs via KIFC3-mediated transport along stress-induced nucleus-to-cilium microtubule arrays 5, and FBF1 ablation effectively reduces senescence burden in irradiation-treated mice 4. In adipose tissue, FBF1 constrains preadipocyte beiging through cilia-regulated PKA signaling and hedgehog pathway suppression 6. Additionally, FBF1 maintains cancer stem cell properties in breast cancer via PI3K/AKT/SOX2 signaling activation 7, suggesting therapeutic potential as a senotherapy and cancer treatment target.