Functions as a protein kinase A-anchoring protein that scaffolds the cAMP-dependent protein kinase holoenzyme. May serve as a point of convergence for MAPK and PKA signaling in cilia (By similarity). Interacts with phosphorylated MAPK1. Interacts with MEK1. Interacts with PKA regulatory subunits PRKAR1A and PRKAR1B (By similarity). Belongs to the flagellar radial spoke RSP3 family.