Figure 2.

PI(5)P Synthesized by PIKfyve Regulates Autophagosome Formation

(A) Schematic representation of pathways for PI(5)P and PI(3)P synthesis/turnover and drugs targeting enzymes involved in these pathways.

(B and C) Western blot analysis of LC3-II and tubulin levels and quantification of LC3-II/tubulin ratio in HeLa cells treated with DMSO or increasing concentrations of YM-201636 for 2 hr in the presence or absence of BAF (mean ± SEM).

(D and E) HeLa cells transiently transfected with Strawberry-ATG16L1 were treated with YM-201636 (100 nM, 2 hr) in HBSS, then fixed and stained for endogenous WIPI-2. Bar, 10 μm. (E) Quantification of ATG16L1 and WIPI2 structures per cell, n = 20 cells (mean ± SEM; n = 3 independent experiments; ^∗∗∗p < 0.001, t test).

(F) Western blot analysis of free ATG12 and ATG5-ATG12 complex levels with anti-HA antibody in HeLa cells transfected with HA-ATG12 and ATG5 and treated with YM-201636 (100 nM, 2 hr) (mean ± SEM).

(G) HeLa cells transfected with GFP-PHD3X and Strawberry-ATG16L1 for 16 hr were left in HBSS for 1 hr, then fixed and imaged on Elyra superresolution microscope. Final visualization was performed as previously described. Bar, 1.13 μm.

(H and I) Western blot analysis of LC3-II and tubulin levels and quantification of LC3-II/tubulin ratio in cells incubated with YM-201636 (100 nM, 2 hr) and loaded with exogenous PI(5)P for the last 1 hr in the presence or absence of BAF (mean ± SEM). See also Figure S2.