CA-4-P activates MLC phosphorylation via Rho-kinase.

(A,B) Confluent endothelial cells were exposed to 1 μM CA-4-P (A) or 30 minutes CA-4-P (B). Cells in panels C and D were preincubated with vehicle, C3 exoenzyme (24 hours, 10 μg/mL), Y-27632 (30 minutes, 10 μM), or ML-7 (30 minutes, 10 μM) before exposure to CA-4-P (30 minutes, 1 μM). Equal amounts of cell proteins (30 μg) were analyzed by Western blotting for di-phosphorylated MLC (P-MLC).