Scientists have invented the first synthetic circuit consisting exclusively of fast and reversible protein-protein interactions. That allows the circuit to generate responses in a matter of seconds.
Synthetic biology offers a way to modify cells to perform novel functions, such as glowing with fluorescent light when they detect a certain chemical. Normally, this is done by altering cells to express genes that can be activated by a certain incoming stimulus.
However, there is often a long delay between an event such as the detection of a molecule and the resulting response, due to the time it takes for cells to transcribe and translate the necessary genes.
Deepak Mishra’s team from the Massachusetts Institute of Technology (MIT) in the United States has now developed an alternative approach to designing such circuits. His approach is based exclusively on fast and reversible protein interactions. This means that there is no waiting for genes to be transcribed or translated into proteins, so circuits can be activated much faster, in a matter of seconds.
The researchers used yeast cells to house their circuitry and created a network of 14 proteins from different living things, including yeast, bacteria, plants and humans. The researchers modified these proteins so that they could regulate each other in the network and produce a signal in response to a specific event.
The new type of synthetic biology circuit is based exclusively on fast and reversible interactions between proteins. (Image: courtesy of researchers, edited by MIT News. CC BY-NC-ND 3.0)
Its network, the first synthetic circuit consisting solely of phosphorylation / dephosphorylation protein-protein interactions, is designed as a toggle switch, a circuit that can switch rapidly and reversibly between two stable states, allowing it to “remember” an event. specific, such as exposure to a certain chemical. In this case, the target is sorbitol, a sugary alcohol found in many fruits.
Once sorbitol is detected, the cell stores a memory of the exposure, in the form of a fluorescent protein located in the nucleus. This memory is also passed on to future generations of cells. The circuit can also be reset by exposing it to a different substance.
This type of circuit could be useful for creating environmental sensors or diagnostic tests that could reveal characteristic states of an impending illness or health crisis, such as a heart attack. (Source: NCYT from Amazings)