Illustration of the cascading effects of a component's deletion and of the elementary signaling modes in signaling networks. (a) The cascading effects of a component's deletion. (b) Elementary signaling modes. In (a) and (b), the ovals denote original nodes or complementary nodes, and the small circles mean composite nodes. In (a), the dashed edges and the dashed node contours indicate the nodes and edges that will be disrupted in the cascading failure following the removal of node A. In (b), the dashed shapes outline two elementary signaling modes (ESMs). Note that different ESMs can have common nodes.