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Flashcards in Protein Targetting Deck (32)
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1

Where are proteins synthesised on free ribosome destined for

Cytosol, nucleus, peroxisomes and mitochondria

2

Where are protein synthesised on the RER destined for

Secretion, insertion into the membrane and lysosomes

3

What sequence do proteins destined to remain in the Er contain?

KDEL sequence

4

Where is the KDEL sequence found on proteins

C terminus

5

What proteins transport proteins with the KDEL sequence back to the ER

COP1 proteins

6

Where is the signal sequence for proteins destined to go to mitochondria found?

N terminus

7

What type of proteins bind to proteins destined to mitochondria

Heat shock proteins

8

What do heat shock proteins do?

Allow proteins to cross the mitochondrial membrane and pull the protein through the translocation machinery

9

What are the 2 translocation machine dies found the in the mitochondrial membranes

TOM (outer membrane) and TIM (inner membrane)

10

What happens to the protein once it enters the mitochondria

The protein folds and the signal sequence is cleaved

11

What is the signal sequence on proteins destined for lysosomes

Mannose-6-Phosphate

12

What do proteins destined for mitochondria contain to be recognised by enzymes that their mannose region needs phosphorylating

Signal patch

13

What happens to proteins once its bound to a M6P receptor

Transported in vesicles with a clathrate coat to lysosomes

14

What causes a dissociation between the receptor and protein

A pH change

15

What enzyme removes the phosphate group

Phophatase

16

What is I cell disease

Deficiency in the Kinase enzyme which phosphorylates the mannose group for proteins destined for lysosomes

17

What is the result of I cell disease

Bloated lysosomes as they don't have enzymes to break down their contents

18

What is the sequence for proteins destined for the nucleus called

Nuclear translocation sequence

19

What binds to proteins destined for the nucleus

Importing

20

What is the role of Ran GTP in protein targeting for the nucleus

Binds to importin causing a conformational change which displaces the cargo protein

21

What is the signal sequence for proteins targeted for peroxisomes called

Peroxisomes targeting sequence

22

Where is the peroxisomes targeting sequence found

C terminus

23

What recognises the peroxisomes targeting sequence

PEX 5 receptors

24

How do proteins destined for peroxisomes enter

PEX proteins make up a complex in th emebrsne and form a pore

25

What is Zellweger syndrome

Syndrome resulting in mutations in PEX proteins.

26

What is cotranslational transport

When proteins move from ribosomes to the Golgi then out of the cell

27

What 2 types of secretion are there

Constitutive or regulated

28

Give an example of constitutive secretion

Collagen

29

Give an example of regulated secretion

Insulin

30

Where is the signal sequence found for proteins destined to be secreted

N-Terminus