protein targeting Flashcards
how are proteins targeted to ER and which types
signal peptide
-secreted, membrane and lysosomal proteins
how are cytosolic proteins targeted to organelles and which types
via other peptide signals
uncle, mitochondrial and peroxisomal proteins
how are proteins rcognised at the ER membrane
-ER signal sequence on
how many amino acids long is a stop transfer sequene
20-22 amino acids
what cleave signal sequences
signal peptidase
what happens to stop transfer sequences after
remain as transmembrane segments of portein
4 pathways for vesicles from golgi
– Integral membrane proteins / membrane phospholipid
– Continuous secretory pathway e.g. extracellular matrix proteins
– Stimulated secretory pathway, stored vesicles e.g. insulin
– To form lysosomes
when in protein synthesis is targeting done
after translatn
before protein folding
what chaperone is protein complexed with
HSP70
what do chaperones do
take proteins to MITOCHONDRION
what to proteins targetted to the nucleus contain
nuclear localisation signal
what does NLS do and need
bind to importin
transported through nuclear pore
requires G-protein Ran and hydrolysis of GTP
what does exportin do
reverse function to NLS - export proteins from nucleus
what are lysosomal proteins tagged with and what does it do
mannose-6-phosphate in golgi
direct proteins into transport vesicles, which become the lysosome
what types of proteins have specific targeting sequences
Nuclear / mitochondrial / peroxisome
