Identification of TG2 in R37 and KP1 cells.

<p>(<b>A</b>) The presence of TG2 and TG1 in R37 and KP1 cells. Whole cell lysates from R37 and KP1 cells were prepared as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057017#s2" target="_blank">Materials and Methods</a>. Western blotting was used to detect the presence of TG2 and TG1 antigen by using the specific monoclonal TG2 antibody Cub7402 and a polyclonal anti-TG2 antibody and a polyclonal antibody against TG1, while α-Tubulin was used as the equal loading standard for densitometric analysis, as shown in the inset histogram (mean ± S.D. from two separate experiments undertaken in duplicate). (<b>B</b>) <b>Detection of TG2 activity in R37 and KP1 cell lysates.</b> A TG2-specific CovTest assay was performed using R37 and KP1 cell lysates (50 µg protein) as described in the Material and Methods. Data represent mean values ± S.D. from 3 separate experiments. (<b>C</b>) Cell surface TG activity was undertaken with live cells (2×10⁴ cells/well). Cells were incubated with biotin-cadaverine in serum free medium for 2 h after plating onto FN coated wells. HRP conjugated Extr-avidin was used to detect the biotin-labelled crosslinking products as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057017#s2" target="_blank">Materials and Methods</a>. Data represent mean values ± S.D. from 3 separate experiments. *, p<0.05 compared to the control sample.