Information transmission and evolution of crosstalk in noisy signal transduction networks

Reliable transmission of information about the environment along cellular signaling pathways is crucial for accurate regulation of cellular function. However, signaling pathways are often highly interconnected, creating signal transduction networks consisting of multiple pathways. How did such complex, interconnected networks evolve and what constraints did the dynamics of evolution place on their architecture? Does crosstalk between pathways necessarily lead to reduction in the amount of information that can be reliably transmitted? In this talk, we will study information transmission and the evolution of cross-talk between noisy signaling pathways with the aim of addressing these and related questions. For this purpose, we develop a sequence-based evolutionary algorithm and evolve networks consisting of more than one pathway based on physically motivated fitness functions. We show how two fitness functions, both related to measures of information transmission, lead to very different evolutionary outcomes, one with a high degree of crosstalk and the other without. We relate the evolutionary outcomes to the fitness landscapes, and discuss the biological implications of our results.