Fig. 4
SEC5-InsP3R interaction facilitates macrophage phagocytosis. a Effect of SEC5 expression on the phagocytosis of C. albicans by BMDMs. Cells were transfected with vectors encoding SEC5-EGFP, EGFP, SEC5-siRNA, or scramble siRNA, and cells were incubated with C. albicans for 30 min (MOI = 10). Phagocytosis index was calculated as the average number of C. albicans ingested by BMDM cells during 30 min. Phagocytosis percentage represents the percentage of BMDMs undergoing C. albicans internalization during 30 min. Data are summarized as the mean ± SEM from three experiments. b Confocal images depicting the localization of SEC5 and InsP3R in resting (upper panel) or activated (C. albicans-infected; lower panel) BMDM cells. c Enhanced co-immunoprecipitation of endogenous SEC5 using antibodies against InsP3R1 in RAW264.7 cell lysates treated with C. albicans (MOI = 10) for 1 h. Lysates from cells not infected with C. albicans were used as a negative control. Quantification of SEC5 immunoreactive bands, normalized to their respective InsP3R1 bands, is shown in the right panel. Bars represent fold change in SEC5 intensity (mean ± SEM from three experiments). d Effect of recombinant cell-permeable H1-TAT peptide on BMDM phagocytosis. BMDM cells were pretreated with H1-TAT or scramble H1S-TAT (2 μM) for 6 h using the same protocol as described in a. e Infected mouse kidney CFU assay. Groups of C57B/L6 female mice were injected via lateral tail vein with 1 × 105 CFU of C. albicans (SC5314) and treated with the indicated peptides. Kidney CFU assays (n = 3 × 3) were performed 24 h after infection. In all panels in a and d, unless otherwise noted, data represent the mean ± SEM from at least three independent experiments (*p < 0.05, **p < 0.005, ***p < 0.001)