Principles of Intracellular Signal Transduction

In the following we shall deal with the basic components and principles of intracellular signal transduction and signal processing. The specific reactions and the various levels of signal transduction will be discussed in detail in later chapters. 

The transduction of a signal in a signaling chain occurs by a sequential activation of the participating proteins. Important mechanisms for the activation of signaling proteins are 

Very often the proteins of a signaling chain are multivalent, i.e. they can receive signals from more than one upstream signaling partner and they can pass on the signal to more than one downstream effector proteins. This property allows a branching of signaling pathways and the formation of signaling networks. 

Another important principle of signaling transduction is the use of diffusible chemical messengers that are formed upon the activation of signaling enzymes. By specifically binding to cognate signaling proteins these are activated for further signal transmission. 

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