KIFBP (kinesin family binding protein) is a molecular regulator of kinesin motor proteins essential for neuronal development and axonal maintenance. Primary function: KIFBP activates KIF1B plus-end-directed microtubule motor activity 1 and simultaneously inhibits specific kinesins (KIF1A, KIF18A, KIF15) by sequestering their motor domains and blocking microtubule attachment 23. This dual regulatory role controls intracellular cargo transport and microtubule dynamics. Mechanism: KIFBP contains a tetratricopeptide repeat α-solenoid structure that distorts kinesin motor domains, preventing their microtubule binding 2. It also interacts with the citron kinase complex at the midbody ring, participating in cytokinesis and midbody maturation 4. Disease relevance: Homozygous KIFBP mutations cause Goldberg-Shprintzen syndrome (GOSHS), characterized by intellectual disability, microcephaly, peripheral neuropathy, and Hirschsprung disease 53. Loss of KIFBP function impairs axonal microtubule bundle integrity through ROS-dependent mechanisms 6, and disrupts neurite growth via cytoskeletal interactions 5. Clinical significance: GOSHS patients exhibit progressive neurological features including ataxia, ophthalmoparesis, and hypogonadotropic hypogonadism 7, indicating KIFBP's critical role in nervous system development and maintenance.