Transgenic constitutively-active myosin light chain kinase (CA-MLCK) expression within intestinal epithelial cells causes intestinal epithelial MLC phosphorylation, intestinal barrier dysfunction, and reduce survival in immune-mediated colitis. Phosphorylated MLC of WT and CA-MLCK Tg mice. P<0.01 (top). Survival after adoptive transfer of CD4+CD45Rbhi effector T cells into RAG1 knockout (blue symbols) and CA-MLCK transgenic RAG1 knockout recipients. Weight loss was far more severe (not shown) and survival was dramatically reduced by CA-MLCK expression. P<0.01 (bottom). From Su et al. 2009. Gastroenterology.