Figure 1

TG2 cross-links Bcr. A) GST-BcrGAP was incubated with guinea pig liver TG2 (Guinea pig TG2) or His₆-tagged human TG2 (Human TG2) that was loaded with GTPγS, or exposed to Ca²⁺ or treated with nothing. GST-BcrGAP was pulled down with glutathione-agarose beads and TG2 bound to it detected by Western blot analysis. B) Bcr-transfected COS-1 cell lysates incubated with the indicated amounts of guinea pig TG2 with or without 5 mM CaCl₂. C) HeLa cell lysates treated with CaCl₂ and guinea pig TG2 as indicated. D) COS-1 were transfected with Bcr and the indicated TG2 constructs. Cell lysates were treated with or without CaCl₂. E) Bcr and TG2-transfected cell lysates were incubated with EGTA and/or CaCl₂ as indicated for 2 h at 37°C. Antibodies used for Western blotting are indicated to the left. Arrows indicate guinea pig TG2 or His₆-tagged human TG2 (A) or Bcr monomer (B-E); single asterisks indicate the top of separating gel; double asterisks indicate the wells of the stacking gel.