BE230_Lecture_23&24

BE230_Lecture_23&24 - Cell Structure & Function...

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Cell Structure & Function BE230 Dr Christine Loscher Lecture 11
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For next day What processes use cAMP? What processes use Calcium? Target tissue, signaling molecule and cell response
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Target tissue/cell Signaling molecule/ligand Second messenger Cell response Muscle cells Acetylcholine Ca Mucle cell contract Heart Adreneline cAMP Increases heart rate and force of contraction Liver Vasopressin Ca Glycogen Kidneys ADH cAMP Maintains osmotic pressure Pancreas Thyroid Acetylcholine TSH Ca cAMP Amylase secretion Syntheis of thyroid hormone
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Enzyme linked receptors They were recognized initially through their role in responses to extracellular signal proteins that promote the growth, proliferation, differentiation, or survival of cells in animal tissues. These signal proteins are often collectively called growth factors , and they usually act as local mediators at very low concentrations. The responses to them are typically slow (on the order of hours) and usually require many intracellular signaling steps that eventually lead to changes in gene expression. Enzyme-linked receptors have since been found also to mediate direct, rapid effects on the cytoskeleton, controlling the way a cell moves and changes its shape.
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Enzyme linked receptors Transmembrane proteins with their ligand-binding domain on the outer surface of the plasma membrane. Instead of having a cytosolic domain that associates with a trimeric G protein, their cytosolic domain either has an intrinsic enzyme activity or associates directly with an enzyme. Whereas a G-protein-linked receptor has seven transmembrane segments, each subunit of an enzyme-linked receptor usually has only one. Six classes of enzyme-linked receptors have thus far been identified:
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Six classes of enzyme-linked receptors 1. Receptor tyrosine kinases phosphorylate specific tyrosines on a small set of intracellular signaling proteins. 2.
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This note was uploaded on 01/05/2010 for the course FSH BT taught by Professor Ianmarison during the Fall '09 term at Dublin City University.

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BE230_Lecture_23&24 - Cell Structure & Function...

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