9-2 Intracell Sorting Flashcards
(41 cards)
Golgi Apparatus the “____”
Golgi Appartus/the “pancakes” function to sort proteins and work within the exocytic network
- Nuclear membranes are ______ with the Endoplasmic Reticulum
2. What size is the Nucleus in comparison to other organelles?
So….Nuclear membranes are CONTINUOUS with the ER organelle!
2.Nucleus is PROMINENT making up of about 10% entire cell volume
ENDosome
Eukaryotic organelle that provides a place for material to be sorted BEFORE IT’S SENT TO LYSOSOME FOR THE KILLING!
The ____ ____ allows proteins to target a specific location within a cell. Where can this actually be found within the protein?
The SORTING SIGNAL (peptide sequence) of a protein allows it to target a specific organelle/location
Sorting Signal is found WITHIN THE AMINO ACID SEQ. of the protein
What’s the difference between a Signal Peptide vs. Signal Patch
Signal Peptide=Linear sequences located at the end of a protein usually
**Signal PATCH= FORMED AFTER PROTEIN FOLDING OCCURS and all sites inteRACT
What Sorting Signal Peptide Sequence do Proteins headed to the
“ENDOPLASMIC RETICULUM/ER” have?
ER Protein signal peptides haveDense (20-30 AA) HYDROPHOBIC CORE!
What Sorting Signal Peptide Sequence do Proteins headed to the
“Mitochondria” have?
Mitochondria signals are [N-terminal amphipathic AlpHA HeliCEs] with hydrophobic AA spaced ~every 4 AA
What Sorting Signal Peptide Sequence do Proteins destined for
“Nuclear Import” have?
Nuclear Import signals are very Basic
“Nuclear importing is very BASIC”
What Sorting Signal Peptide Sequence do Proteins destined for
“Nuclear EXPORT” have?
Nuclear EXPORT signals are LEUCINE-RICH
“They Exported Leucy a long time ago”
What 2 Sorting Signal Peptide Sequence do Proteins destined for
“Peroxisomes” have? [2]
1.Peroxisomal signals are a (c-terminal*SKL-COOH) sequences
[Serine,Lysine,Leucine-COOH]
- (N-terminal) Arg-Leu-X-X-X-X-His-Leu
What happens if a signal directing peptide is removed from 1 factor and then placed on another
That signal would make the NEW protein go to whatever Target the old protein was supposed to go
Which organelle would a protein tagged with a “KDEL” signal peptide go?
KDEL Peptide Sequence= STAY in LUMEN of the ER
“KDEL wanted to stay in the lumen of the ER”
1) How many proteins can pass thru the nuclear pore at one time and which direction do they go?
2) What’s the restriction to this? [3]
3) How many nucleoporins does 1 nucleus have?
1)500 proteins can pass through the nuclear pore/second bidirectionally using cytosolic&nuclear fibrils—WITHOUT TRAFFIC JAMS!
2)Nuclear Pores only permeable to molecules LESS than 60 kDA.
Lrger than tht requires
-active energy gate transport,
-Nuclear localization signal/Import signal for import
-and Nuclear export signal for export
3 *Nucleus has 4000 nuclear pores/cell
What are some organelles that import proteins from the cytosol right after Protein synthesis (post-tl) [4]
- Nucleus (via nuclear pores)
- Mitochondria (TOM and TIM)
- Peroxisomes (destination signal is on C-terminus end of Protein)
- ER (via Sec61 protein to get in and SRP to bind to ER membrane)
A)) Describe the complete Process of Nuclear IMPORTING! [4]
B)Which Ran(s) are the highest concentration INSIDE NUCLEUS?
A))1-cytosolic Protein Cargo[PC] w/Nuclear Import Signal in it binds to importin receptor–>IMPORTIN-COMPLEX!
2- IMPORTIN-C binds to Nuclear Pore and is shuffled into nucleus
3) Once in Nucleus, RanGDP is Given a Phosphate by RanGEF
- ->RanGTP –>which binds to IMPORTIN-COMPLEX & stimulates Protein CArgo to detach from Importin receptor
4) RanGTP + Importin receptor travels to cytosol to restart cycle
B== RanGEF and R-GTP are the HIGHEST CONCENTRATION INSIDE NUCLEUS! “GEF liked to stay INSIDE the Nucleus w/GTP a lot”
A)) Describe the complete Process of Nuclear ExPorTing
“Get it Outta this NucleUS” [4]
B)Which Ran(s) are highest concentration Outside the nucleus?
A) 1-[R-GTP] inside nucleus promotes Protein cargo with Nuclear EXPORT signal to bind to export receptor–>EXPORTANT-COMPLEX
2) Ternary EXC binds to Nuclear Pore fibrils and travels thru pores outside to cytosol
3) Once in cytoplasm RanGAP hydrolyzes bound R-GTP->R-GDP which will DETACH Protein Cargo from Exportant in cytosol
4)Exportant Receptor and GDP separately return to nucleus for recycling
B==B== RanGAP and R-GdP are HIGHEST CONCENTRATION Outside nucleus!
How is Nuclear Import/uptake related to NF-KB and I-Kappa B
When I-Kappa B is phorsphorylated it is no longer able to inhibit
NF-KB(stimulates cell growth/cancer)–>NF-KB goes and gains a nuclear import signal so it can translocate to nucleus=INC cell growth/possible Cancer :-(
What happens to Nuclear Import/Localization signals when the nucleus breaks down for mitosis?
AFter Mitosis, Nuclear Import signals on proteins STAYS PUT so that nuclear proteins can go back to their respective nuclear or cytosol “homes” after nucleus reforms
A–What are the 4 compartments of the Mitochondrion?
B–Where are the Mitochondria Proteins made??
- Matrix
- INNER Membrane
- intermembrane space
- OUTER Membrane
B–Mitochondria Proteins encoded by nuclear genome and made in Cytosol –>then sent to Mitochondria
What are the Main Steps to getting a protein INSIDE the Mitochondria from cytosol?? [5]
After Translation……..
1) AA Signal Peptide seq. on Target Protein directs it to mitochondrias TOM[Translocase of outer membrane] where it binds
2) Trget Protein then “pushed” thru OUTER TOM by chaperone HSP70 and released into intermembrane space after HSP70 ATP hydrolysis
3) unfolded Trget Protein {now in intermembrane space} thens electrophorese into matrix space [due to electrochemcial potential across inner membrane] and finally…
4) Chaperone HSP70 this time “pulls” protein thru TIM[Translocase of inner membrane] and releases it inside mitochondria after HSP70 ATP hydrolysis again –>Woo!
5) Signal peptide seq. IS CLEAVED OFF IN MITOCHONDRIA (opposite of nucleus peptide signals which stays put)
What does HSP60 Mitochondria Chaperone do?
HSP60(Heat Shock Protein) can act as a “GroEL”–>which isolates misfolded proteins using a GroES capped “microwave” –>until protein fixes the misfold itself!
How does Mitochondria Chaperone HSP70 (also used in________) fix misfolded proteins?
HSP70(also used to pull and push target proteins inside Mitochondria) fixes misfolded proteins by binding to hydrophobic domains of the bad protein until it folds correctly. Then it releases it “claws”
Name 3 important functions of the Peroxisome
- OXIDATION OF both Long Fatty Acid Chains and EtOH
- Decomposition of Hydrogen Peroxide
- Synthesis of plasmalogens (myeline membrane lipids)
What are 3 MAIN differences between Mitochondria and Peroxisomes?
1st: MitoChon do MOST of the oxidation w/oxidative phosphorylation
2nd: Peroxisomes use CATALASE redox rxn, detoxifies poisons and use beta-oxidation of fats to make acetyl CoA
3rd: Peroxisomes LACK inner cristae and have a DENSE CORE!
