Components of the S19 and S20 proteasomal subunits localize at primary cilia. (A–E) Immunofluorescence on MEFs of E12.5 WT and Rpgrip1l^−/− embryos. Higher resolution was achieved by using SIM. The ciliary axoneme is marked by acetylated α-tubulin (blue). The TZ is marked by Tctn2 (A) or Rpgrip1l (B and C). (D and E) The ciliary axoneme is marked by acetylated α-tubulin (green) and the BB by γ-tubulin (blue). Psma5 is shown in red. (D) Z-stack of the single optical sections from E with the appropriate plot of the depicted representative image. Bars: (A–C) 0.5 µm; (D and E) 1 µm.