BIOC 311 Lecture Notes - Lecture 26: Isoprene, Farnesyl-Diphosphate Farnesyltransferase, Safingol
18 Jun 2016
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Document Summary
Low cholesterol levels: scap does not bind cholesterol and srebp is released from er membrane and goes to golgi (by cop-ii transport). Srebp will be cleaved by s1p and s2p proteases in golgi and soluble cleaved portion will go in nucleus and activated expression of hmg-coa reductase (rate limiting of endogenous) and ldl-receptors (mediators of exogenous cholesterol). High cholesterol: scap binds and prevent release of srebp and nothing happens. Given different lipids, we can form (1) micelle, (2) bilayer (good boundary) or (3) liposome (vesicles, aqueous lumen, lumen is aqueous) Organelle in cell that is a micelle: no aqueous lumen, all hydrophobic chain are pointing inwards (no water) = lipid droplets, composed of tag and cholesterol ester which are very hydrophobic => love it inside hydrophobic environment. On the other hand, majority of organelles inside body are liposomes. Remember that different tissues and cells have different components, hence different properties.
