Fig. 1: ELIC agonist responses in different lipid conditions.

a Left: Schematic of the sequential mixing experiment for the fluorescence liposomal stopped-flow assay (created with BioRender.com). ELIC proteoliposomes containing the fluorescent Tl⁺ indicator, ANTS, are mixed with agonist (propylamine), and then with Tl⁺ solution after a variable delay time. Right: Representative raw fluorescence traces; the first 0.1 s are fit with a stretched exponential to determine the fluorescence quenching rate, which relates to ELIC channel activity. The legend shows control (no agonist) and different delay times. b Tl⁺ flux rates of WT ELIC in 2:1:1 POPC:POPE:POPG (black) and POPC (red) liposomes as a function of time after mixing with 10 mM propylamine (n = 3). Inset shows activation time course of normalized data. Activation was too fast to accurately determine the rate. c Normalized Tl⁺ flux rates of WT ELIC in POPC, 3:1 POPC:POPG and 1:1 POPC:POPG as a function of time after mixing with 10 mM propylamine (n = 3). d Weighted time constant for the time course of desensitization in response to 10 mM propylamine from the Tl⁺ flux assay for the indicated liposome compositions (n = 3). 2:1:1 indicates 2:1:1 POPC:POPE:POPG. e Same as c showing peak channel activity (rate) in response to 10 mM propylamine from the Tl⁺ flux assay (2:1:1, n = 12; other, n = 3). Statistical analysis was performed using a one-way ANOVA and post-hoc Tukey test. ** indicates p < 0.01 when comparing 2:1:1 with all other liposome compositions. P-values for these comparisons with 2:1:1 are 0.003 for POPC, 0.006 for 3:1 PC:PE, 0.005 for 1:1 PC:PE, 0.002 for 3:1 PC:PG and 0.003 for 1:1 PC:PG. Data are shown as mean ± se for (n) independent experiments. Source data are provided as a source data file.