PI(3)P binding by SNX3 regulates compaction of borreliae. (A–C) Confocal micrographs of macrophages treated with SNX3-specific siRNA#1 and expressing GFP as control (A) or siRNA-insensitive constructs GFP-SNX3 (B) or GFP-SNX3-Y71A (C). Boxes in A–C indicate areas of detail images. GFP signals (magenta; A1, B1, and C1), with internalized borreliae stained by B. burgdorferi–specific antibody (green; A2, B2, and C2), and merges (A3, B3, and C3). Scale bars: 10 µm, and 2 µm in detail images. (D) Top: Statistical evaluation of borreliae compaction in cells treated with SNX3-specific siRNA and expressing indicated constructs. n = 3 (3 × 30 cells). For specific values, see Table S1. One-way ANOVA; *, P < 0.05; **, P < 0.01. Error bars: mean ± SEM. Bottom: Western blots of respective macrophage lysates, developed with SNX3-specific or GFP-specific antibody. The position of respective bands is indicated by arrows on the right, and molecular weight is indicated in kilodaltons on the left. Insens., insensitive.