Lecture 5 - Endomembrane system Flashcards
what does molecular chaperone do
assists polypeptide folding in ER lumen
molecular chaperon - BiP
an ATPase
binds exposed hydrophobic residues
stops proteins from aggregating
molecular chaperone - Calnexin
binds N-glycosylated proteins
WHAT CATALYSES DISULPHIDE BOND FORMATION
oops didnt mean to shout caps lock sry
protein isomerase
where disulphide bond formation occur and why
in ER lumen
cuz is oxidation reaction
and ER lumen is an oxidising environment
what gets added to glycosylate the protein
oligosaccharide
derived from a donor caled dolichol
where N-linked glycosylation occur
ER lumen
why called ‘N-linked’ glycosylation
polysacc transferred onto amino group of the ASPARAGINE (N)
what is glycosylation catalysed by
oligosaccharide transferase (OST)
and ONLY when there’s a ‘consensus sequence’
fucntions of N-glycosylation
assists protein folding
lysosome sorting signal
cell-cell recognition
what is carbohydrate layer on outside of cell called
glycocalyx
name of protein that non-selectively transfers phospholipids between leaflets
scramblase
taking the piss with that name
name of protein that selectively transfers phospholipids between leaflets
flippase
secretory pathway
allows material to move outwards (ER – Golgi – plasma membrane or endosomes/lysosomes)
endocytic pathway
allows material to enter the cell (plasma membrane – endosomes – lysosomes)
role of protein coat during vesicle budding
deform the membrane into a bud shape
and capture the cargo - basically concentrate it all to one spot
name of GTPase that pinches the vesicle off the donor
dynamin
what 2 things guide the vesicle to right spot to fuse
Rab proteins
SNAREs (v and t, complementary)
name of process where v-SNARE interacts with t-SNARE
docking
what does KDEL stand for
LysAsoGluLeu
on the C-terminal of soluble proteins
cis Golgi network function
entry
transport vesicles enter carrying proteins from ER
trans is obvs vice versa
name 2 models that explain how proteins move through Golgi
vesicular transport
cisternal maturation
what part of vesicle budding requires molecular chaperones
uncoating
msot well studied coat protein
clathrin
what helps clathrin attach to the membrane
adaptins
these also
what do o-linked oligosaccharides add on to
-OH side chains of serine and threonine
