Dr. Joseph Schlessinger is one of the first investigators of the field of Signal Transduction, which is essential for cancer research, and numerous other fields as well.
Signal transduction indicates to any process by which cells alter a type of signal. Most signal transduction processes either include sequences which are ordered of biochemical reactions within the cell. These are then carried out by enzymes, activated by second messengers. The overall result is a signal transduction pathway. This usually happens extremely quickly, normally in milliseconds (such as the case of ion flux). Other times this can take minutes for the activation of lipid-mediated and protein kinase cascades. That being said, some such reactions can take many hours, days and even more. This is determined by necessity of the gene expression completion.
The number of molecules and proteins participating in the scenarios with regards to signal transduction expands as the process emanates from the beginning stimulus, and the result is a “signal cascade,” beginning with a relatively tiny stimulus that elicits a much greater response. This is referred to as amplification of the signal.
In single cell organisms as well as bacteria, the variety of process of signal transduction of which the cell is capable of influences the number of ways it can react to its environment. In multicellular organisms, a variety multitude of various signal transduction processes are necessary for the coordination of the behavior and function of the comprising individual cells. This is both understandable and necessary so the whole organism can properly function. As you could expect, more complex organisms have a vast number of signal transduction processes. In addition, getting any stimulus from the outside environment at the cellular level relies on signal transduction.
This is why countless diseases including cancer, diabetes, heart disease and many more are involved with signal transduction and are a result of a defect of the signal transduction pathways. This work is still far from being finished and additional support are needed for the better of us all.