membrane contact sites Flashcards
1
Q
site of lipid synthesis and role in calcium storage
A
smooth ER
2
Q
site of protein synthesis
A
rough ER
3
Q
microscope techniue for localisation of fluorescently labelled proteins to membrane contact sites
A
- CLEM
- correlative light and electron microscopy
4
Q
structure of ER contact sites
A
- ribosomes excluded from contact sites
- membranes are very close (10-80nm)
- ER conteacts can be short or long lived
5
Q
molecular machinery of MCS
A
- tethers
- protein-protein
- protein-lipid
- distance around 30nm
- inihibit fusion
- defined protein and lipid proteome
- enriched in sterols
6
Q
functions of membrane contact sites
A
- provide platforms for:
- calcium mobilisation
- high conc of calcium in ER and less in cytosol
- lipid transfer
- signalling
- organelle division
- calcium mobilisation
7
Q
sensor for calcium mobilisation in ER
A
- stim1
- ER TM protein
- monomeric
- when Ca falls → oligomerisation (join molecules) of stim1
8
Q
ori1 channel
A
- enriched with PIP2 protein
- interacts with stim1
9
Q
what are phosphoinositides
A
- low abundant lipids
- initiate cell signalling
- confer organelle identity
10
Q
site of membrane lipid synthesis
A
ER
11
Q
Niemann Pick Disease C
A
- accumulation of lipids in spleen, liver, lungs, bone marrow, brain
- sphingomyelin accululates in lysosomes
12
Q
diseases linked to MCS
A
- TDP-43 pathologically linked to ALS
- regulates ER-mitochondria contacts
- disease associated mutations in hereditary spastic paraplegia-linked REEP1
- lead to disruptions of ER mitochondria contacts
- presenilins involved in calcium exchange between ER and mitochondria
