Recruitment of the Major Vault Protein by InlK: A Listeria monocytogenes Strategy to Avoid Autophagy
Figure 2
A. InlK amino acid sequence. The signal sequence is underlined and the different regions of leucine rich repeats (LRRs) are outlined. The consensus pentapeptide LPXTG at the C-terminal end is boxed. B. Detection by immunofluorescence microscopy of InlK over-expressing in L. monocytogenes EGD-e (WT), ΔinlK, WT+pADc-inlK, ΔinlK+pPRT-inlK and the ΔsrtA mutant over-expressing inlK (ΔsrtA+pPRT-inlK) grown in BHI medium using the rabbit polyclonal anti-InlK antibody. InlK was detected at the surface of InlK over-expressing bacteria (WT+pADc-inlK and ΔinlK+pPRT-inlK), whereas it was undetectable at the surface WT bacteria or at the surface of the ΔstrA mutant over-expressing inlK. C. Detection of InlK by Western blot on total lysates of L. monocytogenes EGD-e (WT), ΔinlK and ΔinlK+pPRT-inlK grown in BHI using the rabbit polyclonal anti-InlK antibody. Decreased concentrations of recombinant purified InlK were used as a positive control. D. Detection of secreted InlK in the supernatant of ΔsrtA mutants over-expressing InlK. Western blotting was carried out on trichloroacetic acid precipitates of ΔsrtA and ΔsrtA+pPRT-inlK culture (OD600 = 1) supernatants using the rabbit polyclonal anti-InlK antibody. E. Detection of purified recombinant InlK protein with rabbit polyclonal anti-live Listeria antibody, rabbit polyclonal anti-killed Listeria antibody, rabbit polyclonal anti-InlK and a rabbit pre-immune serum. InlK was detected only with the rabbit polyclonal anti-live Listeria antibody indicating that it is expressed during the in vivo infectious process. BSA was used as control protein. Two different amounts of proteins were tested (500 ng and 200 ng) to access signal specificity.