Fig. 1.

Cell-surface expression of Lgr5 or Lgr4 induces the robust formation of membrane protrusions. (A) An on-cell enzyme-linked immunosorbent assay (ELISA) was performed to measure the membrane (live cell stained) and total (fixed, permeabilized and stained) expression of each receptor in HEK cells. The images shown are representative of more than three experiments. (B) Relative membrane expression was determined by calculating the ratio of membrane to total expression values for each receptor and then normalizing to Lgr5_FL across multiple experiments. The data show the mean±s.e.m.; *P<0.05 (one-way ANOVA with Bonferroni post-hoc testing). Confocal optical sections of live cells transiently expressing (C) Lgr5_FL, (D) Lgr5_FL + dynamin-1 K44A (K44A), (E) 834del, (F) Lgr5–V2Rtail (Lgr5/V2Rtail) or (G) Lgr4 to determine their expression at the plasma membrane. HEK cells were transiently transfected with EGFP-tagged (H) Lgr5_FL+K44A, (I) 834del, (J) Lgr5–V2Rtail or (K) Lgr4, imaged live on a confocal microscope and rendered in three dimensions. Scale bars: 10 µm.