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Flashcards in Protein sorting Deck (36):
1

Protein regulation

regulation of the amount of any one protein in the cells controlled at the level of transcription and translation

2

Ubiquitin

a marker in eukaryotic cells that target cystosolic and nuclear proteins for rapid proteolysis

3

Proteasomes

large, multi-subunit protease complexex that recognize and degrade polyubiquinated proteins.

4

molecular chaperone

proteins that facilitate the folding and translocation of other proteins. keeps protein unfolded until completely synthesized

5

faulty chaperone protein

mad cow disease

6

Free ribosomes

although the synthesis of ALL proteins start on free ribosomes, some continue to be synthesized on free ribosomes, while others finish up translation on these free ribosomes as they become membrane bound

7

branches of protein sorting

cystolic (free)
secretory (free and membrane bound proteins)

8

Targets of cystolic pathway

nucleus, peroxisomes, mitochondria, chloroplasts

9

Targets of secretory pathway

Plasma membrane, secretory vesicles, endosomes, lysosomes, extracellular space, ER and Goldi associated proteins, nuclear membrane proteins

10

what decides where protein goes

protein

11

Rough ER

involved in protein metabolism, entry point for most proteins into the secretory pathway

12

Co-translational proteins

translocation of proteins into ER during their synthesis on membrane-bound ribosomes

13

Signal sequence

signal for ribosome attachment to the RER at N terminus, hydrophobic

14

Signal recognition particles, or SRPs

that recognize and bind to signal sequences, while protin is being translated

15

Signal recognition particle receptors

proteins on membrane of the the ER that bind the SRP

16

translocon

membrane channel composed of secretory proteins through with a signal sequence are transported into the ER

17

BiP

molecular chaperone in ER

18

Signal Peptidase

recognizes signal sequence and cleaves it off growing polypeptide chain

19

GTP binding

triggers the transfer of signal sequence into translocon

20

GTP hydrolysis to GDP

dissociation of SRP from SRP receptor and ribosome-mRNA complex

21

Major protein in Secretroy pathway targeted to the RER

Proteins destined for secretion
Intergral membrane proteins

22

Stop Transfer sequence

Alpha Helix, stops the polypeptide from entering the lumen of the ER and changes the conformation of the translocon channel so membrane opens, releasing the polypeptide chain to the ER membrane

23

Trans and Cis face of Golgi

Cis is closest to ER where proteins enter, while trans is furthest from ER, where proteins exit

24

Vesicle protein coats

Clathrin, COPI, COPII
plays key role in ensuring vesicles reach correct targets

25

Lysosomes

membrane closed organelles that contain an array of enzymes capable of breaking down all types of biological polymers at acidic pH

26

mannose 6 phosphate receptor

binds only mannose 6 phosphate which should be only bound to lysosomal proteins

27

snare hypothesis

fusing of different membrane of vesicle is energy dependent

28

Nuclear pore compexes

establishes nuclear composition as unique form the cytoplasm. gene assembly, RNA processing and ribosome assembly

29

Laminin

Nuclear lamina protein

30

Nucleoporins

pore proteins

31

Nuclear localization signals

specific amino acid sequences that are recognized by transport receptors and direct protein transport from cytoplasm into nucleaus through nuclear pore complex

32

Karyopherins

family of transport receptors

33

Importins

karypherins that direct nuclear import

34

Ran

regulates imprtin cargo complex movement. GTP binding protein

35

Nuclear export signals

specific amino acid sequences that target proteins for export out of nucleus

36

Exportins

members of karyopherin family, similar mechanism to importin