Prolonged phosphorylation of STAT-1 serine 727 in cells expressing misfolding forms of HLA-B27 molecule.

<p>U937 transfectants were PMA-maturated, infected with <i>Salmonella enteritidis</i>, and harvested at the indicated time points after excess bacteria were washed away. The phosphorylation of STAT-1 serine 727 was studied by Western blot method with p-STAT-1 Ser727 antibody. Cell extracts (35 µg of each) were loaded on SDS-page gel. <b>A</b>, The representative figure of U937 cells transfected with genomic clones of HLA-B27 (B27g) or with vector alone (mock). “C” denotes uninfected cells. <b>B</b>, The representative figure of U937 cells transfected with mutated, misfolding form of HLA-B27 (B27H9F) or with mutated, non-misfolding form of HLA-B27 (B27E45M). <b>C</b>, The relative intensity of STAT-1 serine 727 phosphorylation in B27g-expressing cells and in mock cells. The bars show the mean ± SD of 6 independent experiments. <b>D</b>, The relative intensity of STAT-1 serine727 phosphorylation in B27H9F- and B27E45M-transfected cells. The bars show the mean ± SD of 5 independent experiments. Blots were stripped and reprobed with STAT-1 antibody and Hsc70 antibody as a loading control. The relative intensity of p-STAT1 Ser 727 was calculated as the intensity of the phosphorylated band divided by the intensity of the respective loading control and normalized to the uninfected control (C, which is given value one). * = <i>P</i><0.05 and † = <i>P</i><0.07 versus 15 min time point of the respective cell line.