Nucleus, Endoplasmic Reticulum, and Golgi Flashcards
Where are SnRNPs made
Cytosol
rRNA transcribed and mixes with proteins to become immature small and large ribosomal units in
nucleolus
Where do ribosomes develop into mature large and small units?`
nucleus
Where do small and large ribosome subunits combine to form ribosome?
outside nucleus in ER
Lamina/Lamins
Intermediate filament that makes meshwork on inside of nucleus to link to proteins
How do proteins and RNA get shuttled from nucleus to cytoplasm
- RAN bound to GDP (indirectly uses GTP)
GDP is high in cytosol so diffuses to low concentration in nucleus - RAN-GEF (Guanine Nucleotide exchange factors) causes RAN to bind to RAN-GTP
Ran-GAP
Removes phosphate once Ran-GTP diffuses to cytosol
Nuclear Importins and Exportins
- Protein that has Nuclear import receptor binds with RAN-GDP as well as a protein with nuclear localization signal
- Once diffuses into nucleus and GDP become GTP, GTP helps take nuclear recptor back out
Polysomes
mRNA in cyotsol being made into protein by ribosomes
Co-Translational Translocation
Most common way for protein to be inserted into ER Membrane or lumen of ER.
Signal translated at same time protein is.
Post-Translational Translocation
Signal for protein to be inserted into Membrane or Lumen of ER is made at a different time than the protein itself
What about proteins that snake in and out of membrane?
These proteins are able to snake in and out based on the charge of the amino acids
Glycosylation in ER
sugars attached to protein to sort protein once in ER
How are proteins sorted to their place, specifically into and out of the ER
Proteins carry signals where to direct them (whether cytosol, ER, Membrane etc.)
If inside ER:
- binds to exit signal cargo receptor
- exit cargo receptor/cargo translocate to form vesicle filled with very specific type of protein
Sorting in Golgi
Vesicles from ER fuse with Golgi Body and proteins work their way through the stacks of Golgi. Starting at Cis end and leaving at Trans end of Golgi
