The premature activation of the pancreatic digestive enzyme, trypsinogen to trypsin, in the pancreatic acinar cell is considered to be one of the main initiating events in acute pancreatitis [198,201,202]; in this experimental model of acute pancreatitis, this required the CCK activation of PAK2 (Figure 4 and Figure 7 and Table 2). The gene discussed is PAK2; the disease is acute pancreatitis.