Fig. 1

Identification of Desmoglein-2 as a new extracellular target for HpHtrA in vitro. A Peptides identified with proteomic analysis are highlighted in yellow in the hDsg2 protein sequence (UniProt Q14126), which consists of an extracellular domain (bold), a linker region followed by a transmembrane domain (underlined), and an intracellular domain (italicized). B Peptograph of hDsg2 peptides identified in supernatant of cells treated with HpHtrA wt and inactive mutant HpHtrA SA. Left side of the peptograph shows sequential positions of peptides identified in specific gel sections, while right side shows the number of peptide spectral counts detected in corresponding gel sections. C 100 ng recombinant rDsg2 were incubated with indicated amounts of recombinant HpHtrA wildtype (wt) or 1 µg inactive HpHtrA (SA) for 16 h at 37 °C. Proteins were separated by SDS-PAGE and analyzed by Western blot. rDsg2 was detected using an antibody recognizing the extracellular domain of hDsg2 (rDsg2^FL). HpHtrA was detected by using a polyclonal HpHtrA antibody. D 40 µg protein lysate of NCI-N87 (lanes 1–3) or MKN-28 cells (lanes 4–6) were incubated with 250 ng HpHtrA wt or inactive HpHtrA SA for 16 h at 37 °C. Proteins were separated by SDS-PAGE and analyzed by Western blot. Full length hDsg2 (hDsg2^FL) and full length hCdh1 (hCdh1^FL) were detected by using antibodies recognizing the extracellular domains of hDsg2 and hCdh1. Overlay of hDsg2 (green) and hCdh1 (red) was presented to exclude possible cross reactions of the anti-hDsg2 and anti-hCdh1 antibodies. Loading control was performed by the detection of GAPDH and HpHtrA