PSL300H1 Final: L3 Receptors & Signaling
7 Jan 2017
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Lecture outline: signal transduction and hormones, receptor structure and function, basic signaling pathways and amplification, off switches, signal transduction and hormones. Variable number in target cell (500 100,000 when upreg. ) Numbers regulated by hormone levels or self-regulated. Binding is saturable and reversible (bind and release ligand) Activity must have an off switch for each receptor (diff/loc) Zn helps to position estrogen in receptor. Receptor forms u-shape with beta sheet at base critical for functioning to bind to appropriate region of nuclear dna. Otherwise no change in response to estrogen. Every receptor has a different 3d structure that determines what happens once the receptor is activated. Here, conformation is important to bind dna (steroid receptor) If cytosol, once hormone is bound, it will translocate from cytosol to nucleus because both receptor types interact with. Bind lipid soluble hormones for activation (steroids, thyroxine) Receptor-enzyme receptors (receptors with intrinsic enzyme a(cid:272)ti(cid:448)it(cid:455), so do(cid:374)"t need to activate another enzyme e. g. , insulin)
