Topic 4, Lecture 3 Flashcards
Why is it important that we understand protein transport to the endoplasmic reticulum?
It is the beginning of the secretory pathway and all proteins that are not sent to peroxisomes, mitochondria, and nucleus MUST be sent to the ER for modifications.
Rough ER
Covered with ribosomes, site of protein synthesis, looks like sheets
Describe the anatomy of the ER
Stacks of pancakes, tubules are on the outside, massive network that functions to send extensions
Describe the massive network extensions of the ER
All parts of the cytosol are close to some part of the ER, (reticulum-a fine network or netlike structure), (heminuclear formation-half-way wrapped around the nucleus)
Smooth ER
Site of lipid synthesis
Describe the relationship between the smooth and rough ER
Smooth and rough ER is the same thing but protein synthesis doesn’t happen on the smooth section
How long is the ER signaling sequence?
16-30 amino acids
Where is the signaling sequence?
N-terminus
ER signaling sequence amino acid nature
hydrophobic amino acid core
ER signaling sequence cleaved or permanent?
Cleaved
Microsomes
Completely experimental, first seventy amino acids are important (perfect number)
ER transport co-translational or post-translational
Co-translational
Discuss the signal recognition particle
Made by RNA polymerase III, RNA-protein complex, slows elongation by recognizing and binding to the translational pause domain of the ribosome in order to move the ribosome to Sec61
Analogy of the SRP hinge subunit
Elbow
Elongation factor binding site
Must be bound to the large ribosomal subunit in order to translate mRNA
