FIGURE 1. Example of an obligate combinatorial signalling network.
From the following article:
Scott W. Lowe, Enrique Cepero and Gerard Evan
Nature 432, 307-315(18 November 2004)
doi:10.1038/nature03098
Programme 1 drives proliferation and apoptosis, and Programme 2 blocks both. For each cell fate, dominant components are shown as thick lines. Concerted activation of both programmes together leads to cell expansion because Programme 1 overcomes the growth inhibition of Programme 2, and Programme 2 overcomes the lethality of Programme 1. However, activation of either programme on its own triggers cell-death (Programme 1) or senescence (Programme 2).