(F) Confocal images of live GRAMD1 TKO HeLa cells expressing either wild-type (WT) or mutant versions of EGFP-tagged GRAM domain of GRAMD1b (EGFP-GRAM1b) constructs as indicated. Cells were treated with SMase (100 mU/ml for 1 hour at 37°C) before imaging. Insets show at higher magnification the regions indicated by white dashed boxes. Anionic lipid sensing defective mutants (K161A, R191A, and K161A/R191A), a cholesterol sensing defective mutant (R189W), and a cholesterol/anionic lipid sensing defective mutant (R189W/R191A) are shown. Note the absence of (R189W, R189W/R191A, and K161A/R191A) or significantly reduced (K161A, R191A) PM recruitment of the mutant versions of EGFP-GRAM1b compared to the strong PM recruitment of wild-type EGFP-GRAM1b (WT). Scale bars, 10 µm. 