BIO-2600 Lecture Notes - Lecture 5: Cortisol, Lac Operon, Adenylyl Cyclase
29 Mar 2018
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Document Summary
Signal transduction is the molecular mechanism by which cells: receive incoming stimuli, convert and amplify the signal internally through second messengers, alter effector proteins, ultimately change cell behavior. One signal transduction pathway, neuro-transmission at the synapse. Another example would be the control of lactose catabolism in bacteria via the lac operon. Multicellular organisms have several forms of cell signaling communication. Earl sutherland had a signaling conundrum; epinephrine is administered to the outside of liver cells while glycogen phosphorylase is a cytosolic enzyme. Sutherland hypothesized that a second messenger , different from the first messenger epinephrine, somehow communicated epinephrine binding to its receptor on the surface of the cell to the activation of glycogen phosphorylase inside. Sutherland got the nobel prize in 1971 for his discoveries, which were foundational for the entire signal transduction field. Signal transduction often acts as a series of molecular switches. Turning off a switch is as important as turning it off.
