Fig. 3.

ATL depletion leads to increased acetylation and stability of MTs but does not change +TIP dynamics. (A) COS7 cells treated with scrambled siRNAs (SCR) were analyzed by immunofluorescence with antibodies to β-tubulin and to α-tubulin acetylated at K40. The boxed areas are enlarged and shown on the right. (Scale bar, 10 µm.) (B) As in A but ATL2 and ATL3 were depleted (ATLdKD). (C) The mean intensity of acetylated α-tubulin is determined in SCR and ATLdKD cells, which are segmented as described in Fig. 1B. (D) COS7 cells treated with SCR siRNAs were treated with the MT depolymerization drug colchicine for 0 min, 15 min, and 12 h, and MTs and the ER were visualized with antibodies to β-tubulin and CRT, respectively. (Scale bar, 10 µm.) (E) As in D but ATL2 and ATL3 were depleted (ATLdKD). (F) COS7 cells were transfected with EB1-GFP marking the +TIPs of growing MTs. Live cell imaging of control and ATL-depleted cells (SCR and ATLdKD, respectively) was performed to track the movement of +TIPs. (Scale bars, 10 µm.) (G) Quantification of +TIP velocity and track length as well as track lifetime. (N = 8,684 +TIP tracks in 11 SCR cells; n = 4,021 +TIP tracks in 16 ATLdKD cells.)