Protein Targetting Flashcards
Where are proteins synthesised on free ribosome destined for
Cytosol, nucleus, peroxisomes and mitochondria
Where are protein synthesised on the RER destined for
Secretion, insertion into the membrane and lysosomes
What sequence do proteins destined to remain in the Er contain?
KDEL sequence
Where is the KDEL sequence found on proteins
C terminus
What proteins transport proteins with the KDEL sequence back to the ER
COP1 proteins
Where is the signal sequence for proteins destined to go to mitochondria found?
N terminus
What type of proteins bind to proteins destined to mitochondria
Heat shock proteins
What do heat shock proteins do?
Allow proteins to cross the mitochondrial membrane and pull the protein through the translocation machinery
What are the 2 translocation machine dies found the in the mitochondrial membranes
TOM (outer membrane) and TIM (inner membrane)
What happens to the protein once it enters the mitochondria
The protein folds and the signal sequence is cleaved
What is the signal sequence on proteins destined for lysosomes
Mannose-6-Phosphate
What do proteins destined for mitochondria contain to be recognised by enzymes that their mannose region needs phosphorylating
Signal patch
What happens to proteins once its bound to a M6P receptor
Transported in vesicles with a clathrate coat to lysosomes
What causes a dissociation between the receptor and protein
A pH change
What enzyme removes the phosphate group
Phophatase