Impairment of Listeria protrusion formation by overexpression of the cytoplasmic tail of CD44. Impairment of Listeria protrusion formation by overexpression of the cytoplasmic tail of CD44. (A–E) SEM analysis of Listeria protrusions in parental RT4 cells (A, C), RT4 cells expressing wild‐type CD44 cytoplasmic tail (B, D) and a mutated version of the CD44 cytoplasmic tail (E). In control cells and in cells expressing the mutated CD44 cytoplasmic tail, Listeria induced the formation of long protrusions (arrow in (A)), which are connected to the cell surface through a thin stalk (facing arrowheads in (C, E)). Conversely, in RT4 cells expressing wild‐type CD44 cytoplasmic tail, the protrusions are shorter (arrow in (B)) and characterised by a thick and distorted proximal portion (arrowhead in (D)). Stars indicate the position of bacteria. Scale bar: 2 μm (A, B); 0.8 μm (C); 0.3 μm (D); 1 μm (E). (F) Quantification of the number of Listeria protrusions in control RT4 cells and in RT4 cells expressing wild‐type or mutated forms of CD44 cytoplasmic tail. Expression of wild‐type CD44 cytoplasmic tail impairs protrusion formation, whereas its mutated variant had no effect. Error bars indicate one standard deviation from the mean. Sascha Pust et al. EMBO J. 2005;24:1287-1300 © as stated in the article, figure or figure legend