CCV actin patches facilitate vesicle fusion via docking and clustering of late endocytic vesicles to the CCV membrane.

(A) LAMP1⁺ vesicles fuse with the CCV at actin patches. Live cell images of a Vero cell at 3 dpi expressing lysosome-GFP (LAMP1) and actin-RFP. (B) Latrunculin A (LatA) treatment redistributes LAMP1⁺ clusters at actin patches around the CCV to the juxta-nuclear region (white arrows). Live cell images of a Vero cell at 3 dpi expressing lysosome-GFP (LAMP1) and actin-RFP. (C and D) LatA treatment redistributes VAMP7⁺ clusters at actin patches to the juxta-nuclear region (white arrows). Vero cells at 3 dpi were treated with LatA for 10 min prior to fixation and immunostaining for F-actin, VAMP7, and NMII. Histogram depicts the mean intensity ± SD of ≥ 60 cells for at least 3 independent experiments. Statistical significance was determined using Student’s t-test (****P <0.0001). NMII, C. burnetii Nine Mile phase II strain. Scale bar, 2.5 μm.