Figure 2.

Generation of fragmented R2 and R3 in the in vivo acute pancreatitis model. A–I, mice received three injections of saline or caerulein hourly. Pancreata were then removed, homogenized, and prepared for Western blot (WB) detection. Samples from DT40–3KO cells stably expressing R2 I-III and R2 I-IV or R3 I-III and R3 I-IV were run on the same gels to indicate the relative sizes of the fragmented receptors. R2 and R3 were fragmented in pancreata from mice treated with caerulein (A and F). Statistics showed that there was a significant reduction in the full-length receptors (B and G) and a concomitant substantial increase in the fragmented receptors (B–D and G–I). The N-terminal fragments of R2 were co-immunoprecipitated (IP) with the C-terminal fragments using the C-terminal R2 antibody CT2, suggesting that the receptor remains associated after proteolysis (E). Each experiment was repeated four times. The arrows in A, E, and F indicate major receptor fragments. *, statistical significance determined by Student's t test. GAPDH, glyceraldehyde-3-phosphate dehydrogenase.