Figure 2
From: Topological estimation of signal flow in complex signaling networks
Topological information and signal flow. (a) A biochemical reaction such as phosphorylation of a protein in signaling networks can be represented by a directed link with a sign (i.e., a signed edge of a digraph). Activation and inhibition are denoted as plus (+) and minus (−) signs, respectively. (b) Signal flow is estimated by calculating the multiplication of the link weight and the activity of source node. (c) There are four types of signal flow. The sign of link and the sign of signal flow can be same or opposite depending on the source node activity and link weight where pointed arrow (→) indicates a positive weight and blunt arrow (⊣) denotes a negative weight.
