Nucleo-cytoplasmic transport Flashcards
Proteins found in the nucleus
transcriptional regulators
Proteins found in the plasma membrane
channels, receptors, secreted proteins, transporters
organellar proteins
resident proteins (in the lumen), membrane proteins
gated transport
between the cytosol and nucleus via nuclear pores
transmembrane transport
via transmembrane proteins
vesicular transport
via vesicle “ferries”
What would make a particular peptide sequence a sorting signal.
Its amino acids as well as signal patches (specific 3-D arrangements)
how does indirect immunofluorescence work?
1) fix cells
2) permeabilize cells
3) insert immobilized antigen A into protein
4) add primary antibody directed against antigen A
5) add secondary antibodies directed against primary antibody,
how does fluorescent protein tagging work?
1) insert DNA encoding peptide tag into gene for protein of interest
2) introduce into cell
3) protein is fluorescent
what is the nuclear envelope?
surrounds the nucleus and is composed of two membranes that are continuous with the ER membrane
punctuated by nuclear pore complexes
what are nuclear pore complexes?
site of transport between nucleus and cytoplasm
has cytosolic fibrils on cytoplasmic side and nuclear basket on nuclear side
also has disordered region of channel nucleoporins in the center of the channel
What gets passed through nuclear pore complexes?
Fully folded proteins, Protein
and ribonucleoprotein complexes
Does transport create order or disorder?
Transport creates order –> requires energy
import into nucleus requires what kind of signal?
NLS (bound by importins)
-Pro-Pro-LYS-LYS-LYS-ARG-LYS-Val
capitalized ones are the signal
export from nucleus requires what kind of signal
NES
-MET-Glu-Glu-LEU-Ser-Gln-Ala-LEU-Ala-Ser-Ser-PHE-
