Poc1 promotes normal Fop1 protein incorporation into BBs. (A) Poc1 and Fop1 are not required for each other’s localization to BBs. Poc1:mCherry or Fop1:mCherry BB levels do not change in response to knockdown or complete loss of the reciprocal protein, respectively. (B) Fop1 BB levels increase upon Poc1 overexpression (OE). Sas6a overexpression is a negative control. (C) Poc1 BB levels do not change upon Fop1 overexpression. (A–C) Bars, 0.5 µm. n = 150 BBs. (D) Representative Fop1:mCherry image denoting new BB assembly. Quantification of protein incorporation into new BBs is measured using the background-subtracted intensity levels of daughter BBs divided by mother BBs. This measurement is acquired relative to the separation distance of mother and daughter BBs. Bars: 10 µm; (inset) 0.5 µm. (E) The rate of Fop1 incorporation at new BBs decreases in poc1Δ cells. (left) Fop1:mCherry levels relative to BB separation. (right) Quantification of Fop1:mCherry protein incorporation relative to mother-daughter BB separation distance. (F) Poc1:mCherry incorporation into BBs does not change in Fop1 KD cells. (left) Poc1:mCherry levels relative to BB separation. (right) Quantification of Poc1:mCherry protein incorporation relative to mother–daughter BB separation distance. (E and F) Dashed line represents mean distance upon which ciliogenesis occurs (2.6 ± 0.1 µm). Bars, 1 µm. Mean ± SEM; *, P < 0.01.