By Anna Kolchinski
The Elowitz Lab at Caltech has discovered a crucial difference in the way cell signaling was previously thought to have worked. Prior to the lab's paper, which was recently published in Cell, similar ligands, which act as cellular signaling proteins, were thought to have been nearly indistinguishable by the cell. However, this was shown to be inaccurate as the two slightly different ligands had different signaling patterns. Specifically, the Notch cell communication system, which plays a part in cancer development, was examined. In the Notch system, the Delta1 and Delta4 ligands, which have similar structures, are sent out to bind to the same receptors and trigger cellular cascades which result in the activation of transcription factors. Transcription factors are signals that tell DNA which portions should be made into proteins to express that particular gene at the time. Before, it was not understood how such similar ligands could trigger different transcription factors if they bound to the same receptors. But, based off of this research, in which different fluorescent molecules were attached to the different ligands to show the ligand release patterns, the two ligands act in unique ways. Delta1 ligands simultaneously bound to many receptors, while Delta 4 ligands seemed to bind to only one, but many times in succession. These two different patterns of binding explain how the same receptors can distinguish between the two different types of ligands, thus triggering different responses. Overall, binding pattern as a mechanism for cell signalling is a relatively new concept that should be explored further to uncover how it is used generally in signalling pathways.
California Institute of Technology. (2018, February 16). Cells communicate in a dynamic code: A critically important intercellular communication system is found to encode and transmit more messages than previously thought.. ScienceDaily. Retrieved February 25, 2018 from www.sciencedaily.com/releases/2018/02/180216150338.htm