(B) Quantification of the ratio of PM signals to the cytosolic signals of wild-type EGFP-GRAM1b (WT) and mutant versions of EGFP-GRAM1b (R166L, Q173I, F182I, T184V, F186L, G187L, A188S), as assessed by confocal microscopy and line scan analysis from GRAMD1 TKO HeLa cells, expressing indicated constructs, as shown in (C) and Fig EV4A (mean ± SEM, n = 10 cells for each condition; data are pooled from one experiment; Dunnett's multiple comparisons test, **P < 0.0001). 