The molecular signaling systems of complex cells are nothing like simple electronic circuits. The logic governing their operation is riotously complex — but it has advantages.

Back in 2000, when Michael Elowitz of the California Institute of Technology was still a grad student at Princeton University, he accomplished a remarkable feat in the young field of synthetic biology: He became one of the first to design and demonstrate a kind of functioning “circuit” in living cells. He and his mentor, Stanislas Leibler, inserted a suite of genes into Escherichia coli bacteria that induced controlled swings in the cells’ production of a fluorescent protein, like an oscillator in electronic circuitry.
It was a brilliant illustration of what the biologist and Nobel laureate François Jacob called the “logic of life”: a tightly controlled flow of information from genes to the traits that cells and other organisms exhibit.
But this lucid vision of circuit-like logic, which worked so elegantly in bacteria, too often fails in more complex cells. “In bacteria, single proteins regulate things,” said Angela DePace, a systems biologist at Harvard Medical School. “But in more complex organisms, you get many proteins involved in a more analog fashion.”

Philip Ball
Quanta 16 September 2023 – Read More