Endomembrane System Part 2 - Golgi

Question 1

who discovered the Golgi complex

Answer 1

Camillo Golgi

Question 2

morphology of Golgi complex

Answer 2

complex/stack of flattened, membrane bound cisternae with dilated edges and numerous associated tubules and vesicles

Question 3

what does the number and distribution of golgi complexes vary between

Answer 3

different cell types

Question 4

what does the mammalian cell typically contain

Answer 4

one large golgi complex near centre of cell

Question 5

what do plant and yeast cells typically contain

Answer 5

several golgi complexes located throughout cell

Question 6

what does the golgi complex have due to the several subcompartments

Answer 6

distinct polarity both structurally and functionally

Question 7

where is the cis-golgi network located

Answer 7

cis face of golgi complex

Question 8

what does the CGN consist of

Answer 8

complex interconnected network of tubules and vesicles adjacent to ERES

Question 9

what is the CGN the initial destination for

Answer 9

COPII transport vesicles from ERES

Question 10

what do incoming vesicles do in the TGN

Answer 10

fuse to form larger vesicles and interconnected tubules

Question 11

what does the CGN serve as

Answer 11

a sorting station

Question 12

what is the CGN a destination for

Answer 12

1. acceptor compartment of COPII vesicles coming forward from ERES to CGN (anterograde transport)
2. COPI vesicles moving back from next subcompartment of golgi (retrograde transport)

Question 13

what is the CGN the site of

Answer 13

1. COPI vesicle assembly for transport back from CGN to ER (retrograde)
2. forward transport as CGN matures into next subcompartment of Golgi (anterograde)

Question 14

3 main sections of golgi cisternae

Answer 14

cis
medial
trans

Question 15

what are cisternae the site for

Answer 15

golgi metabolism

Question 16

where is the trans golgi network (TGN) located

Answer 16

trans face of golgi complex

Question 17

what is the trans golgi network

Answer 17

interconnected network of tubules and vesicles

Question 18

what does the TGN serve as

Answer 18

sorting station

Question 19

what does TGN sort

Answer 19

forward transport as previous subcompartment of golgi matures into TGN

Question 20

what is the TGN the site for

Answer 20

1. clathrin coat vesicle assembly for anterograde transport from TGN to endosomes
2. secretory vesicle and secretory granule assembly for anterograde transport to pm
3. COPI vesicle assembly for transport back to golgi trans cisternae

Question 21

structure of golgi

Answer 21

CGN
cis-cisternal
medial cisternae
trans cisternae
TGN

Question 22

what is the organization of the golgi complex mediated by

Answer 22

golgi matrix

Question 23

what does the golgi matrix consist of

Answer 23

various golgi peripheral and integral membrane proteins

Question 24

what does the golgi matrix’s cytoplasmic facing domain do

Answer 24

interact to form scaffold that links everything together

Question 25

what do GRASPS serve as

Answer 25

tethering proteins to link different golgi sub compartments together

Question 26

what else does the golgi matrix link the golgi complex to

Answer 26

cytoskeleton

Question 27

main golgi complex function

Answer 27

glycosylation

Question 28

what are most glycoproteins that move through the golgi subjected to

Answer 28

additional glycosylation reactions

Question 29

what is completed in the golgi complex

Answer 29

N-linked glycosylation

Question 30

what do cis, medial and trans golgi cisternae possess that modify glycoprotein's N-linked core oligosaccharides

Answer 30

unique glycosyltransferase and glycosidase enzymes

Question 31

what do the golgi cisternae act as

Answer 31

an assembly line where core oligosaccharides on proteins get modified sequentially by different enzymes in each subcompartment

Question 32

what does alpha-mannosidase I in cis cisternae do

Answer 32

removes 3 mannose sugars from core oligosaccharide in glycoprotein

Question 33

what is another main function of the golgi complex

Answer 33

M6P sorting signal

Question 34

what do other modifications to oligosaccharide core in golgi complex serve as

Answer 34

sorting signal for lysosome

Question 35

what occurs with mannose-6-phosphate (M6P)

Answer 35

in cis-cisternal, mannose units in core oligosaccharides of soluble proteins destined for lysosomes are phosphorylated

Question 36

what does M6P serve as

Answer 36

a signal patch for soluble lysosomal protein targeting

Question 37

what does N-acetylglucosamine phosphotransferase recognize

Answer 37

unique sequences in lysosomal-destined proteins

Question 38

what does the addition of M6P resides prevent

Answer 38

lysosomal-destines proteins from being subjected to N-linked glycosylation reactions

Question 39

what occurs to proteins without M6P

Answer 39

packaged at TGN into secretory transport vesicles/granules destined for plasma membrane/extracellular or reside in golgi

Question 40

what occurs to proteins with M6P

Answer 40

packaged at TGN into clathrin coated transport vesicle to endosomes vis the M6P receptor and biosynthesic pathway

Question 41

what is the signal patch that M6P groups serve as

Answer 41

targeting signal consisting of specific 3D arrangement of molecules on folded protein's surface

Question 42

what is the cisternal progression/maturation model

Answer 42

what each subcompartment matures into: cis-->medial-->trans->TGN

Question 43

what does is mean that golgi sub compartments are dynamic structures

Answer 43

each subcompartment continually moves forward from cis to trans side of golgi - mediated by golgi matrix

Question 44

what changes while moving through the golgi complex

Answer 44

composition of each subcompartment

Question 45

how does the golgi complex persist

Answer 45

because COPI transport vesicles continually move resident golgi proteins back to proper subcompartment

Question 46

what gets excluded from COPI vesicles

Answer 46

cargo destined for post-Golgi compartment in endomembrane system

Question 47

what do clathrin coated vesicles from TGN target

Answer 47

with M6P-bearing protein cargo, target endosomes

Question 48

what do secretory vesicles from TGN target to

Answer 48

plasma membrane

Question 49

what do secretory granules from TGN target

Answer 49

eventually plasma membrane

Question 50

what do COPI-coated vesicles from TGN target to

Answer 50

back to trans golgi cisternae