MOLBIOL 3B03 Lecture Notes - Lecture 4: G Protein–Coupled Receptor, Adenylyl Cyclase, Signal Transduction
5 Jan 2017
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Document Summary
Cells respond to wide variety of signals. Signals can be in the form of proteins, small chemicals, gases, light and heat. Depolarization opens ca2+ channels allowing extracellular ca2+ to flow in. This releases ach which results in the influx of na+ which depolarizes the muscle plasma membrane. Signaling molecules can act locally or at a distance. Short range signal membrane bound signal molecule. Long range signal signaling cell releases ligand into the environment where it binds to receptors on several target cells. Ligands are stabilized by local mediators and facilitate the interaction with receptors. They are programmed to respond to specific signals that lead to activation of distinct signaling pathways. Cell can respond different to the same signal. Depends on cellular environment, receptors and intracellular proteins. Scaffold proteins control of the efficiency and specificity of signal. Scaffold proteins organize signalling complexes that relay signals with precision, speed and efficiency. Ensure that receptors are activated in order in downstream signals.
