Lecture 6 Flashcards
exocytosis
process where newly synthesized proteins are expressed and transported to destinations
-needs proteins synthesis to start
ribosomes
2 subunits-small and large
- in cytoplasm
- mRNA in nucleus needs to get into cytosol
Shine delgarno sequence
prokaryotes have these sequences.
proteins that require modifications or that are destined to be membrane bound integral proteins go to
otherwise, the making of proteins starts in the
ER
cytosol
(ER signal sequence) SRP
signal recognition particle
- binds to ribosome and signal peptide
- It has sequence of amino acids that says go to this place, and its called a signal sequence.
- directs transport of ribosome to ER
small and large subunit
floats around separately. mRNA will be recognized by small subunit, then large subunit will add on top then translation, starts creating protein
in mRNA
UTR
untranslated region and there is 5’ cap in eukaryotes. have a start somewhere internal. start site called: Kozak sequence (in euk*)
large subunit composed of what
E:eject; P: polymerize; A:add.
problems w GLUT5
doesnt transport glucose, it is a fructose transporter.
SRP comes in,
ribosome pauses translation. When its bound, and drags to ER. SRP binds to SRP receptor. once they interact, ribosome docks on sec 61. Allow proteins to cross membrane. SRP and SRP receptor displaced and recycled.
as protein gets made it is jammed into
lumen (space) of ER
Sec61
protein translocator or translocon
allows peptides to cross from cytosol to ER lumen
allows release of peptides in plane of ER
signal sequence means
N terminus is in
New N terminus is the green loop. Cleaved by protein complex called
signal peptidase. Signal peptide gets cleaved off.
if it has 12 transmembrane domains,
it has 12 internal signal sequences
