Physiology 3140A Lecture Notes - Lecture 15: Protein Structure, Insulin, Growth Factor
28 Dec 2017
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Document Summary
Target cell responds by means of a receptor protein which specifically binds the signal molecule then initiates a responds. Two major classes of receptors: cell surface receptors. Hydrophobic molecules are released on their carrier protein and can passively diffuse through the plasma membrane into cells. Some signal molecules [ligands] diffuse across membranes and bind to receptors in either cytosol or nucleus. Many diverse ligands, but have similar mechanism of action regulate gene transcription. Purpose: regulate gene transcription: do not signal a lot might not signal at all. Inhibitory protein stops the nuclear receptor from binding to the dna. Conformational rearrangement of proteins: co-activator protein may bind (or not) = change in shape of protein, there is binding to the appropriate binding site of dna and activation of gene transcription after the change in shape. There is not always an activation of gene transcription, there can be a repression of gene transcription.
