FIGURE 10.

Illustration of the proposed mechanism for activation of PLC by U73122. The highly lipophilic U73122 (green, red, and blue) binds covalently to PLC (gray and purple ribbon structure) via cysteine residues (yellow) increasing the affinity of the protein for cell membranes. One or more U73122 molecules serve as lipid anchors for the modified protein allowing it to dock within the cell membrane, in close proximity to substrate, thus leading to increased catalytic activity. See “Experimental Procedures” for details regarding generation of model.