Most proteins in the ERare glycosylated

Proteins in cytosol arerarely glycosylated

original precursor oligosaccharide addedto most proteins in the ER

Protein glycosylation in the rough ER

Oligosaccharides are used as tags to mark the state of protein folding

Misfolded proteins are exported from ER and destroyed

Chapter 13

Intracellular Vesicular Traffic

Roadmap ofprotein trafficinside cell

Endocytic and secretory pathways

red = secretorygreen = endocyticblue = recycling

5.14

Figure 5.14

figure 05-14.jpg

Vesicular transport

There are various types of coated vesicles

Different coats are used for different transport steps in the cell

Coated Pits are the sites of receptor mediated endocytosis

Clathrin protein

cytosol

Material to be taken up by cell

Clathrin-coated pits and vesicles

Structure clathrin triskelion

Arrangement oftriskelion on surfaceof clathrin coatedvesicle

DVD Clip 57

Assembly and disassembly of clathrin coat

Dynamin pinches clathrin coated vesicles from the membrane

Electron micrograph from Drosophila mutant

Resting Chemical Synapse

Drosophila mutant can not recycle synaptic vesicles

SNARE proteins guide vesicular transport

Active Chemical Synapse

Interaction of SNARE proteins while docking synaptic vesicle at nerve terminal

Model for membrane fusion. Tight SNARE pairing forces water molecules from areabetween lipid bilayers

Exam Iaverage 81.2%median 84%

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