Fig. 1: Cellular and vesicular H+ permeability in the calcifying primary mesenchyme cells (PMCs) of the sea urchin larva.
From: Proton channels govern vesicular carbonate chemistry in mineralizing cells of a marine calcifier
A Representative confocal fluorescence and bright field images of PMCs along the spicules showing luminal pH of endocytotic vesicles measured using carboxy-SNARF. Arrows point to the dye in the skeleton after longer incubation. Scale bars, 40 µm and 20 µm (insets). A′ Proportion of vesicles within individual cells with alkaline (N = 51), neutral (N = 28), and acidic (N = 33) pH conditions. Box plots represent median (middle line), 50% of data (box), and minima and maxima (error bars). B, B′ Representative traces and measurements of changes in PMC vesicular pH induced by changes in external pH in control and nigericin-treated PMCs. Values presented for individual cells as mean ± SEM (N = 19: controls; N = 19: nigericin pH 8, 6, 7; N = 15: nigericin pH 9), unpaired t-test, *P = 0.0114, **P = 0.00045 for pH 8, **P = 0.0027 for pH 9. C, C′ Representative traces and measurements of pHi and pHves conditions in the PMCs during changes in pHe. Values presented for individual cells as mean ± SEM (N = 22: cytosolic; N = 29: vesicular), unpaired t-test, ****P < 0.0001. D, D′ Representative traces and measurements of pH conditions in endocytotic alkaline vs. acidic vesicles during changes in pHe. Values presented for individual cells as mean ± SEM (N = 10: alkaline; N = 11: acidic), unpaired t-test, ****P < 0.0001, ***P = 0.0002.
