Posted by: Dan | August 25, 2007

Basic Concepts: Signal Transduction

The Emergent Integrated Circuit of the Cell

Did you know that Wikipedia has a good entry for signal transduction? While I prefer the schematic from Hanahan and Weinberg (2000), they’ve got some good summaries. Their introduction to this area of research is as follows:

In biology, signal transduction refers to any process by which a cell converts one kind of signal or stimulus into another, most often involving ordered sequences of biochemical reactions inside the cell, that are carried out by enzymes and linked through second messengers resulting in what is thought of as a “second messenger pathway”. Such processes are usually rapid, lasting on the order of milliseconds in the case of ion flux, to minutes for the activation of protein and lipid mediated kinase cascades. In many signal transduction processes, the number of proteins and other molecules participating in these events increases as the process eminates from the initial stimulus, resulting in a “signal cascade” and often results in a relatively small stimulus eliciting a large response.

In bacteria and other single-cell organisms, the variety of signal transduction processes of which the cell is capable influences how many ways it can react and respond to its environment. In multicellular organisms, a multitude of different signal transduction processes are required for coordinating the behavior of individual cells to support the function of the organism as a whole. As may be expected, the more complex the organism, the more complex the repertoire of signal transduction processes the organism must possess. Thus, sensing of both the external and internal environment at the cellular level, relies on signal transduction. Many disease processes such as diabetes, heart disease, autoimmunity and cancer arise from defects in signal transduction pathways, further highlighting the critical importance of signal transduction to biology as well as medicine.

The overview nicely summarizes the various signaling molecules, their receptors, and second messengers, focusing on the most well-studied of them.
For a reference list, check below the fold:


  1. Nice presentation and well described.But if the topics were described in different levels (M.Sc/Graduation/Twelvth ), then that would be better for students.
    Thanking You


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