(a) Confocal micrographs of HeLa cells expressing yellow fluorescent protein (YFP) fused to Nap1, Sintbad or Tank and infected with S. Typhimurium, stained for ubiquitin (Ub) 2 h after infection. At least 100 cells were analyzed. DAPI, 4,6-diamidino-2-phenylindole. Scale bar, 10 μm; arrowheads, bacteria shown in insets. 