Summary: Input­output robustness in simple bacterial
signaling systems
Guy Shinar*, Ron Milo*
, Mari´a Rodri´guez Marti´nez*, and Uri Alon*
*Departments of Molecular Cell Biology and Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
Edited by John J. Tyson, Virginia Polytechnic Institute and State University, Blacksburg, VA, and accepted by the Editorial Board October 31, 2007 (received
for review July 20, 2007)
Biological signaling systems produce an output, such as the level of
a phosphorylated protein, in response to defined input signals. The
output level as a function of the input level is called the system's
input­output relation. One may ask whether this input­output
relation is sensitive to changes in the concentrations of the sys-
tem's components, such as proteins and ATP. Because component
concentrations often vary from cell to cell, it might be expected
that the input­output relation will likewise vary. If this is the case,
different cells exposed to the same input signal will display
different outputs. Such variability can be deleterious in systems
where survival depends on accurate match of output to input. Here
we suggest a mechanism that can provide input­output robust-
ness, that is, an input­output relation that does not depend on

Source: Alon, Uri - Departments of Molecular Cell Biology & Physics of Complex Systems, Weizmann Institute of Science

Collections: Biology and Medicine