Title: Noise filtering in cellular signaling networks
Speaker: Michael Hinczewski (Assistant Professor of Physics, Case Western Reserve University)
Abstract: Cells process and transmit information about their environment through complex signaling cascades. The accurate transmission of the information is crucial for normal function, with defects in the cascades linked to a host of cancers. As in many designed communications systems, these biological circuits must cope with noise that inevitably corrupts the signal. How to efficiently filter noise, to reconstruct the best estimate of the input, has been a key problem in engineering. One of the great advances in this area was a mathematical framework developed by Norbert Wiener and Andrey Kolmogorov during the Second World War, originally inspired by the need to filter noise in the targeting of anti-aircraft systems. We show that cells effectively implement the same mathematical solution encoded within the chemical reaction network of a kinase-phosphatase push-pull loop, a basic unit of signaling pathways. To demonstrate this, we generalize the ideas of Wiener and Kolmogorov to deal with some of the challenges that arise in the biological context, including signaling through discrete changes in molecular populations, and the highly nonlinear relation between input and output. We can thus provide mathematically rigorous bounds on the performance of biochemical noise filters, and highlight features of the system relevant for optimizing filter efficiency.