Fig. 3

CCPs differentially regulate the initiation of cilia formation. A Immunoblotting analysis demonstrated the deglutamylation activity of GFP-tagged murine CCP1, CCP4, CCP5, and CCP6 when the lysates of their expressing HEK293T cells were incubated with porcine tubulin. CCP1, 4, and 6 reduced the immunoreactivity of polyE, which recognizes the long polyglutamate chain, while CCP5 specifically decreased the immunoreactivity of GT335, which recognizes the branch point glutamate. B hTERT-RPE1 cells transfected with GFP or GFP-CCPs were serum-starved for 24 h and immunostained with GFP (green) and ARL13B (red) and nuclei visualized with DAPI (blue). C Quantification of the ciliation in GFP-positive cells (3 independent experiments; at least 30 cells analyzed per experimental condition, Additional file 2) revealed that overexpression of CCP5 and CCP6 inhibited cilia formation. In contrary, overexpression of CCP1 and CCP4 did not alter the rate of ciliated cells. Error bars represent s.d. ∗  ∗ , P < 0.01, Student’s t test. Scale bars: 10 µm