2.4 Intracellular compartments and protein sorting 2 Flashcards
Pertaining to Nucleus Cytosol, fibrils interact with what?
Import proteins
Pertaining to Nucleus Cytosol, what does the nuclear basket do?Where is it located?
Is inside the nucleus. Tethers active genes to NPC. Regulated transport
Dealing with nuclear import, What is the NLS?
Sorting signal with + AAs. Usually internal.
What recognizes the NLS?
NIR or importins.
What do Importins do?
ferry cargo into nucleus.
Pertaining to nuclear export, what is the NES?
Nuclear export sorting sequences that contain + and - AAs.
What recognizes the NES?
NER or exportins.
What do exportins do?
Ferry cargo into cytosol.
What is shuttling pertaining to nucleus
We can go in and out both ways. Shuttle proteins back and forth.
pertaining to shuttling, what is a powerful regulatory strategy?
compartmentalization
Regulation of recognized signal sequence is by what 3 things?
Phosphorylation, proteolysis, and inhibitor proteins
What are karyopherins?
Importins and exportins.
What requires energy to pass through the nuclear pore? What energy does it use?
Anything large. GTP
What is Ran?
GTPase
Where is Ran-GAP only found? What does it do?
Cytoplasm. Catalyzes the removal of phosphate.
Where is Ran-GEF only found? What does it do?
In nucleus. Exchanges GDP to GTP.
How doe this GTPase system work with exporting?
Nucleus to cytosol. Ran-GTP in nucleus, associates with Exportin. Once in cytosol, Ran-GAP (hydrolysis of GTP by removing Phosphate) releases cargo.
How doe this GTPase system work with importing?
Cytosol to nucleus. Ran-GTP releases the cargo, that association initiates recycling of importin back to cytosol. Once importin in cytosol it releases Ran-GDP.
Pertaining to cytosol –> mitochondria transport, how many compartments are there?
- Outer membrane (OM). Intermembrane (IMS). Inner membrane (IM) and Matrix.
What complexes are found in the OM?
TOM, SAM, MIM