Sorting, the RER, and the Golgi

Question 1

Signal peptides

Answer 1

N-terminal extensions composed of 5-30 basic/hydrophobic AA

Question 2

Signal patches

Answer 2

Distant parts of protein sequence brought together upon folding

Question 3

Types of translocation

Answer 3

Post-translationally (C)

Co-translationally (N)

Question 4

Post-translational translocation characteristics

Answer 4

SOluble and posses patch or signal peptide

Question 5

Sorting into the nucleus

Answer 5

Uses NLS (short, basic squences on N-terminus of proteins)
Importin comes in with protein, uses Ran-GTP to get out

Question 6

Sorting into mitochondria process

Answer 6

Precursors protein with MTS…binds receptor…moves to protein translocator…pulled into protein and signal sequence cleaved by peptidase

Question 7

Sorting into mitochondrial membrane

Answer 7

Matrix targeting sequence binds TOM protein of outer…pulls through into TIM…TIM recognizes the intermembrane space-targeting sequence and diffuses over to protease…protease will cleave the matrix targeting sequence and the intermembrane space targeting seqence stays in inner membrane

Question 8

Intermembrane space sorting

Answer 8

Intermembrane space targeting sequences pass through Tom receptor

Question 9

Outer membrane mitochondrial proteins sorting

Answer 9

Hydrophobic transmembrane signal…recognized by TOM, passed to SAM, mim and mdm act and released into membrane

Question 10

Peroxisomes sorting process

Answer 10

C-terminal and N-terminal ends…peroxisomal targeting sequence binds pex5 receptor…receptor binds pex14 receptor on membrane…moves through via pex 10 and 12

Question 11

Co-translational translocation

Answer 11

Used for proteins that are secreted, membrane bound, resident in ER, golgi, or lysosomes

Question 12

Signal for co-translational translocation

Answer 12

N-terminal signal of hydrophobic residues

Question 13

Process of co-translational location

Answer 13

SRP binds to N terminal signal sequence…SRP binds to SRP receptor on ER membrane surface associated with translocon…GTPase activity of both SRP and SRP receptor results in opening of the translocon…signal peptidase claves the signal sequence

Question 14

What is attached into the ER

Answer 14

N-linked glycosylation

Linked to asparagine - X - serine/threonine

Question 15

What is in the ER membrane that holds the glycosylation chain?

Answer 15

Dolichol

Question 16

Glucosidase

Answer 16

Chews the oligosaccharide attached to the protein

Question 17

ERAD system

Answer 17

Sends misfolded proteins for degradation

Question 18

Glycosylated proteins that pass ERAD

Answer 18

Encapsulated in transition vesicles and transported via anterograde transporrt

Question 19

Surface of vesicles from ER t oGOlgi coated with

Answer 19

COP2

Question 20

Modifications in Golgi

Answer 20

O-linked oligo added to serines and threonines

Mannose-6-P added to proteins goign to lysosomes

Question 21

Cis golgi network

Answer 21

Phosphorylation of oligosaccharides on lysosomal

Question 22

Cis cisterna

Answer 22

Removal of Man

Question 23

Medial cisterna

Answer 23

Removal of man and addition of GlcNAc

Question 24

Trans cisterna

Answer 24

Additon of Gal

Question 25

Trans GOlgi netowkr

Answer 25

Addition of NANA (common sialic acid)

And sortint

Question 26

Glycosylation purposes

Answer 26

Sorting
Stabilization of secreted proteins and transmembrane with extracellular domains
Biomolecule recognition

Question 27

Golgi to lysosomes

Answer 27

Binds to M6P receptor…travels in vesicle with clathrin coat to the early endosome…M6P dissociated…Endosome fuses to lysosome

Receptor recycled

Question 28

Secretory vs. transport vesicles

Answer 28

Secretory - regulated exocytosis

Transport - constitutive exocytosis