PapE induces the release of CpxP from CpxA.

<p>A) mSPINE experiments were performed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107383#pone-0107383-g002" target="_blank">Fig. 2A</a> with <i>E. coli</i> TG1 producing CpxA-Strep and either CpxP (WT) or the cleft mutant CpxPA108V (A108V) without or with PapE co-expression. Due to reduced CpxA-Strep level, mSPINE samples co-expressing PapE were five-fold stronger concentrated than samples without PapE. To allow comparison, immunoblots were cut into an upper and lower part. The upper part was probed with antiserum against CpxA and the lower part with antiserum against CpxP. Immunodetection was carried out for both parts simultaneously. Black triangles show specific and the white triangle unspecific reactions. Shown are representatives of three biological replicates. B) To visualize protein level in each mSPINE experiment, whole cells from (A) were collected after formaldehyde treatment, subjected to immunological determination using antiserum to CpxA, CpxP, and MalE (loading control). Purified CpxA-His6, His6-CpxP and MalE served as controls for antibody specificity (C). Black triangles show specific and white triangles unspecific reactions.