The KIF3B/B/KAP3 tail domain specifically facilitates TRIM46 transport to the axon initial segment

Intracellular transport is essential for neuronal organization, yet how motor proteins achieve cargo selectivity remains incompletely understood. Kinesin-2 motors transport diverse cargos through the heterotrimeric KIF3/KAP3 complex, but whether variations in assembly composition contribute to functional specificity has been unclear. This study provides evidence for heterogeneity in neuronal KIF3/KAP3 assemblies, including a KIF3B-enriched, KAP3-associated population in addition to the canonical