Fig. 1.

Overexpression of human SPL and human SGPP1 in insulin-secreting INS1E cells. Shown are (A) gene and protein expression of human SPL and human SGPP1 measured by qRT–PCR and Western blotting, (B) S1P concentration measured by ELISA and content of the most abundant PE (phosphatidylethanolamine, PE 34:1, 36:1, 36:2, and 38:4) measured by mass-spec; changes in S1P and PE content are shown as % of concentrations in INS1E-ctr cells, n = 4. (C) representative immunofluorescence pictures (from n = 2) after staining with antibodies for the detection of rat and human SPL and SGPP1 (green-SPL, red-SGPP1; note that since both primary antibodies were rabbit, a double immunostaining for parallel detection of SPL and SGPP1 in the same cells was not possible). Shown are Means ± SEM from four independent samples. ANOVA followed by Bonferroni, ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001 versus INS1E-control cells. The magnitude of SPL and SGPP1 overexpression was regularly checked during the entire time of cell culture.