As a component of IFT complex A (IFT-A), a complex required for retrograde ciliary transport and entry into cilia of G protein-coupled receptors (GPCRs), it is involved in ciliogenesis. Involved in retrograde ciliary transport along microtubules from the ciliary tip to the base. Component of the IFT complex A (IFT-A) complex. IFT-A complex is divided into a core subcomplex composed of IFT122:IFT140:WDR19 which is associated with TULP3 and a peripheral subcomplex composed of IFT43:WDR35:TTC21B. Interacts directy with IFT122, WDR35 and TTC21B. Associated with microtubules. Localized at the distal tip of the cilium. Belongs to the IFT43 family.