L15- endocytosis Flashcards
name the cellular uptake mechanisms
- phagocytosis
- macropinocytosis (fluids)
- clathrin coated vesicles
- non coated vesicles
- caveolae
describe the mechanism of phagocytosis
- chemotaxis to the bacteria
- receptors that bind bacteria activate
- cytoskeleton protrudes and forms ‘zippers’ around the particle, phagosome sealed around bacteria by plasma membrane
- cytoskeleton breaks down
- phagosome fuses with lysosome (phagolysosome)
- particle degraded by enzymes
- residual body (indigestible material) discharged
what is macropinocytosis
uptake of fluid
removal of growth factor receptors from plasma membrane
explain mechanism of macropinocytosis
- GF’s stimulate actin driven protrusions of plasma membrane creating large vesicles around fluid + nutrients (forming macropinosome)
what are the actin based protrusions triggered by GF receptors called?
ruffles
what can macropinocytosis prevent?
formation of cancer and tumour cells
what is clathrin mediated endocytosis dependant on
dynamin
is non clathrin mediated endocytosis dependant on dynamin?
can be dependant or not
what is caveolin mediated endocytosis
non clathrin mediated endocytosis dependant on dynamin
receptor mediated endocytosis enables what
specificity
what receptors mediate iron uptake and where are they found and what type of receptor are they
transferrin
blood stream
constitutive
what is constitutive receptor mediated endocytosis
endocytosis of receptor continuously, whether or not a ligand is bound
what substance regulates specificity
RAB - GTPases
what role does F-actin have in endocytosis
F-actin polymerisation has a supporting role in vesicle scission.
What provides energy for fusion of a vesicle with its target membrane during membrane trafficking
conversion of trans-SNARE to cis-SNARE
