BIOL 2021 Chapter Notes - Chapter 12.1: Glycosylphosphatidylinositol, Intermembrane Space, Protein Folding
28 Jan 2018
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Document Summary
New lipids are inserted into the cytosolic leaflet of the smooth er. Scramblase is responsible for flip flopping lipids from one leaflet to another: equilibrates lipids in the 2 leaflets, not specific for any lipid flip flops them randomly. We don"t want this because we need to have different compositions of lipids on either side of the leaflet (asymmetry) Misfolded proteins are exported out of the er and are destroyed by a proteosome in the cytosol. Same process to get into the inner membrane space. Protease cleaves off the stop transfer sequence and the protein is released in the intermembrane space. Membrane anchor inside the lumen of the er which will later be outside the cell. Proteins are asymmetric in the plasma membrane. This asymmetry is created during the its formation. Polyribosome: many ribosomes in a row translating the same mrna. Same pool of ribosomes are used for free (cytosolic) and membrane-bound proteins (on the er membrane)
