Figure 1.
Role of Helicobacter pylori CagL Y58/E59 mutation in type IV secretion-dependent delivery of CagA in host cells.
(A) Cartoon representation of the crystal structure of CagL (molecule A of the six crystallographically independent molecules, PDB accession code 3ZCJ) from strain 26695 [12]. The various α helices (denoted 1–6), R76 and D78 of the RGD-motif and the amino acids N58 und E59 are highlighted. The amino acids from T52-N57 are not resolved and are shown as a dashed line. This region connects the two indicated helices, α1 (D22-S50) and α2 (E59-K101). The PyMOL program was used to generate the structure illustration (The PyMOL Molecular Graphics System, Schrödinger, LLC). (B) Alignment of amino acid sequences of CagL (position 39–78) among strains 26695 [2], Hp0621, Hp0412, Hp0710, Hp0902, Hp1035, Hp1393 [3] and the 26695 CagLYE mutant produced here is shown. A variable region among the CagL proteins between positions 58–62 is boxed in yellow and the Y58/E59 polymorphism is highlighted with red. The strains originated from gastritis (GA), duodenal ulcer (DU) and gastric cancer (GC) patients as indicated [3]. (C) AGS gastric epithelial cells were infected with the indicated H. pylori strains and cagL mutants for 8 hours. Resulting protein lysates were probed with the indicated antibodies as described. The experiments were done at pH 7.4, which gave very strong phospho-CagA signals in a recent study [1]. (D) Quantification of CagA phosphorylation signals in panel C using the luminescence image analyzer. The strongest signal in lane 1 was set as 100%. The data are representative from three independent experiments.