BIO 121 Lecture Notes - Lecture 7: Phosphorylation, Tunxis Community College, Glycosylation
23 Nov 2020
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Document Summary
Consists of er, golgi, lysosomes, endosomes and secretory vesicles. Processing of proteins for export, lysosomes, and proteins entering the cell. Once in er, never enter the cytosol (without a vesicle) 3 subdivisions of endomembrane system: secretory pathway, lysosomal pathway, endocytic pathway. Must start at either end of the system: protein processing. Folding: improper folding is prevented by chaperone proteins which provide a secluded/isolated space for a protein to fold, misfolded proteins go to proteasome to be destroyed so aa"s can be reused. Formation of disulfide bridges: 3d structure held by disulfide between cystenine residues (disulfide isomerase, typically not found in cytosolic proteins. Glycosylation (for proteins destined for the exterior of cell) 3 types of proteins that enter from er (other option is exterior of cell: proteins destined for secretion, plasma menmbrane proteins, proteins destined to be endomembrane resident proteeins. Consists of flattened cisternae and tubules, continuous with nuclear envelope.
