Golgi Apparatus Flashcards
Delivery of protein
- protein synthesised
- amino acids at C-terminus directs protein to location or synthesised as it is being delivered
Golgi discovery
by Italian Camillo Golgi in 1898
Golgi being the site of carbohydrate synthesis
in plants - pectin and hemicellulose
in animals - proteins decorated with sugar sidechains
importance of sugar side chains
added within Golgi
for function of a protein added by glycocyltranferase
sorts and dispatched proteins made in the ER
function of secretory vesicles
package proteins to deliver to plasma membrane
fuses with membrane and secrete to extracellular space
location of cis and trans faces
cis and trans face either side of medical cisternae
face opposite sides of Golgi
sides of Golgi contains….
different enzymes and function
movement of vesicles (process)??
dynamic process
movement of vesicles method
- vesicles budded off from ER
- fuses into membrane of Golgi
- protein passes into Golgi and transported to different location
recycling of protein
back to Golgi and retrieved by ER
retrograde transport done by COPII
ER to Golgi method
- COPII coat buds off by vesicles
- vesicles shed COPII coat and fuse = vesicular tubular cluster
- fuses with cis Golgi
2 ways in which protein may move through Golgi
- moves between cisternae and reach trans Golgi network and release
- vesicle binds to cis Golgi and moves along network
COPII function
recognise protein embedded in membrane
recruit protein with exit/transport signals
Kdel receptor
retrieves proteins back to ER
Kdel receptor method
- C-terminus and mechanism for protein to be retained within ER
- recognises protein in wrong place and binds to receptor
- packages in vesicles in retrograde transport
COPI
budded off from Golgi - may g o back to ER
Clathrin
different signal is budded off to different location
targets specific vesicles
to endosome or membrane to extracellular space
Glycosylation of proteins in Golgi
addition of different types of sugars at different region of Golgi
first step of glycosylation of protein out of 6
sorting
phosphorylation of oligosaccharides on lysosomal protein
2nd step of glycosylation
removal of MAN
3rd step of glycosylation
removal of MAN * addition of GkNAC
4th step of glycosylation
addition of Gal * addition of NANA
5th step of glycosylation
sulfation of tyrosines and carbohydrates
6th step of glycosylation
sorting into destination vesicles
determine where proteins are going
example of sugars formed
N-linked onto asparagene
further sugar decoration on protein
can be further added or trimmed
difference between cisternal maturation and vesicle transport
- linked
- one is through one Golgi to another
- another matures as they go - cisternae through Golgi
