CEP90 is critical for BBS4 localization at centriolar satellites.

(A–B) The CEP90-depleted RPE-1 cells were co-immunostained with the antibodies specific to OFD1 (A) or CEP290 (B), along with PCM-1. (C) The cells were co-immunostained for PCM-1 and BBS4. Insets are magnified views of the PCM-1 granules. (D) The number of cells with OFD1, CE290 and BBS4 at the PCM-1-granules was counted. Over 200 cells per experimental group were analyzed in 2 independent experiments. (E) Cilia formation was induced by serum starvation for 24 hours. The cells were immunostained with antibodies specific to BBS4 and acetylated-tubulin. The number of cells with BBS4 at their cilia counted with over 300 ciliated cells in 3 independent experiments. The graphs show the mean values and standard errors (D, E). (F) Depletion of BBS4 with two specific siRNAs in RPE-1 cells. GAPDH is a loading control. (G) PCM-1 and CEP90 were co-immunostained after BBS4 depletion with siBBS4-2. Scale bar, 10 μm.