class 28 - vesicle transport/membrane trafficking

vesicles

small membrane-encolsed seacs that transport items in/out cells

exocytosis

exit cell

endocytosis

enter cell

coat proteins

on vesicles that determine direction and final destination of vesicle contents

types of coat proteins

clatherin, COPI, COPII, petromer

clatherin-mediated endocytosis steps

assmebly, bud formation, vesicle formation, uncoating, tether, dock, fusion

clatherin-mediated endocytosis assembly

cargo receptors on plasma membrane bind cargo and adaptins

clatherin-mediated endocytosis bud formation

adaptins recruit clatherin to the membrane

clatherin-mediated endocytosis vesicle formation

clatherin naturally forms a sphere

clatherin-mediated endocytosis uncoating

once free, clatherin and adaptins dissociate

clatherin-mediated endocytosis tether

Rab proteins on vesicle connects with a tethering protein on target membrane

clatherin-mediated endocytosis dock

v-snares (on vesicles) and t-snares (on plasma membrane) connect

clatherin-mediated endocytosis fusion

v-snares and t-snares twist together until membranes fuse

outcomes of endocytosis

recycled by recylcing endosomes or broken down by lysosomes

applications of endocytosis

nutrient uptake, defense via phagocytosia

application of exocytosis

cells secrete proteins and molecules into extracellular matrix in process called secretory pathways, final step in secretory pathways is exocytosis (ex. extracellular signaling and membrane synthesis)p

phagocytosis

immune cells can kill pathogenic bacteria pha

phagocytosis process

phagosome fuses with lysosome, lysosome break down bacteria into nutrients for various meetabolic processes