Cell Bio Ch 15

Front 1

How do mitcho., chloroplasts, peroxisomomes, nucleus and ER get proteins??

Back 1

from cytosol

Front 2

How does the glogi, lysosomes, endosomes, and nuclear memberane get proteins?

Back 2

Via ER

Front 3

Signals Sequences
Import to ER
retention in ER lumen
import into Mitcho.
import into nucelus

Back 3

import to ER - eight AA, hydrophobic (n-terminus) like Leu, Ara, Val)
retention-- C terminus (Lys (+), Asp, Glu, Leu) (postive, nega, negat charge)
import into mitcho - - positively charged lys and Arg
import into nucleus...lys, lys, lys Arg (all postive charged, grouped together)

Front 4

what is sorting signal (sorting sequences)?

Back 4

Amino acid sequence that directs protein into the right organelle

Front 5

What if there is no sorting signal?

Back 5

Stays in cytosol

Front 6

::Import to nucleus::
in general (3)

Back 6

selective gates - - nuclear pores
active transport

Front 7

traffic in the nuclear pore can travel both ways? at the same way?

Back 7

yes in both ways at the same time

Front 8

what about small water soluble molecules?
What about large marcomoleulces (like mRNA and proteins)

Back 8

Small water soluble molecules are free to enter by water filled channels in the pore
Must enter by pore and must have signal sequence

Front 9

what is the signal sequence called for the nucleus?

Back 9

nuclear localization signal
or nuclear exist signal

Front 10

Describe the transport into the nucleus?

Back 10

1) Prospective nuclear proteins bind to the nuclear localization signal,
2) which interacts with the fibrils of the pore (pulls them to pore)
3) The protein binds to pore and it opens up
4) Hydrolysis of GTP to bring it other side

Front 11

::Import to nucleus::
what happens to prospective proteins?

Back 11

gets transport back to cytsol, recycles

Front 12

::Import to nucleus::
proteins in are moved in ___ folded conformation?

Back 12

full

Front 13

::Import to nucleus::
nuclear signal sequence is
for import (NLS)
and export (NES)

Back 13

NLS - rich in *lys, arg, His

and export, rich in leucine

Front 14

::Import to nucleus::
signal sequence can be linear or patch?

Back 14

linear - simple at the end
or
patched - several regions that will bind together to form signal.

Front 15

::Nuclear stuff again::
transport across nuclear envelope can be driven by?
why important?

Back 15

Access to NLS
Nuclear factor of activate t-cell moves in to nucleus from high calcium levels immune response activated

Front 16

::into ER::
two types of transport into ER?

Back 16

water soluble proteins across both membranes
and prospective which is embedded

Front 17

::into ER::
names of the site and area with the protein gets transported?

Back 17

contact site (special site where inner and outer memberane meets)
protein translocator channel

Front 18

::into ER::
Describe the transport of water-soluble proteins?

Back 18

1. Signal -recognition particles bind to protein while it's still translating.
2. Slows translation along polyribomsome
3. SRP meets with the SRP receptor on ER memberane
4. SRP gets released and now the ploypeptide channels are threaded into the translocation channel
5. Signal sequence remains bound to channel as ployribosome reactives
6. after c-terminus, gets released

Front 19

::into ER::
Does the signal sequence come off?

Back 19

yes during the polypeptide chain creation the signal gets cut off

Front 20

::into ER::
what happen to signal after it cuts off?

Back 20

it gets embeded into membrane and recycled

Front 21

::into ER::
signal peptidase does what?

Back 21

cuts of the signal sequence

Front 22

::into ER::
What is the pug?

Back 22

inactives the channel

Front 23

::into ER::
stop-transfer sequence does what??

Back 23

releases the chain from channel
the part free floats in the memberane,
forming a alpha helix spanning the memberane

Front 24

::into ER::
start-transferase sequence does what??

Back 24

it starts tjhe whole ER thing
except
it's internal rather then at n-terminus
and never gets removed.

Front 25

::into ER::
what if you wanted a transmemberane protein that spains membrane several times?

Back 25

several pairs of stop and start transfer sequences....

Front 26

::into mitchon::
in general

Back 26

moved post-tranlationally and unfloded at contact sites

Front 27

::into mitchon::
describe what happens

Back 27

1) The signal is recognized by signal on mitch.
2) transported unfolded by protein translactor
3) chaperon helps to pull it across and also folds it.

Front 28

::into mitchon::
does the signal sequence get cut off?

Back 28

yes by signal peptidase

Front 29

::into mitchon::
what does it get lipids?

Back 29

ER

Front 30

::into mitchon::
what about signal sequence?

Back 30

has some postive charged (lys and arg)
amphipathic and an alpha helix

Front 31

::into mitchon::
names for the receptors?

Back 31

TOM/TIM

Front 32

::modification in ER::
name in general two types of modification

Back 32

disulfur bonds
and
glycoproteins made

Front 33

::into mitchon::
describe the disulfur bonds

Back 33

between cysteine
for extra protection

Front 34

::into mitchon::
describe glycosylated

Back 34

oligosachard side chain get placed on protins

Front 35

::into mitchon::
how are the sugars added

Back 35

en bloc, up to 14 at a time

Front 36

::into mitchon::
what are the sugars initially attached to?

Back 36

dolichol

Front 37

::into mitchon::
they get transfered to the ____ end of ___ amino acid

Back 37

nh2 end
of asparagues (asp)

Front 38

::into mitchon::
The asp is part of what sequence?

Back 38

Asp - x - serine
Asp - x - threonine

Front 39

::into mitchon::
what if a protein in ER isnt folding correctly and wants to transport?

Back 39

it wont, chaperons will try to fix it but it not will degrade

Front 40

::into mitchon::
cystic fibrose

Back 40

degration of the lungs,
a calcium channel is mutated and would work prefectly normal...however gets degraded...

Front 41

::methods for studying protein import::
describe some

Back 41

radioactive labeled proteins with isolated organelles
signal ones enter organnels
centifuge
signals will be with organelles in test tube

or add protease which eat away at non-signal
adding detergent will break up organneles

Front 42

::methods for studying protein import::
describe with use of micrsome

Back 42

if you add microsome (small vesciles from break up organnels) and use western block. Proteins with signal sequence never entered cell (mitch only I guess)

Front 43

Describe secretory pathway

Back 43

start with ER, goes to gogli and to cell surface

Front 44

Describe endocytic pathway

Back 44

endosome from cell surface and goli meet and form lysosome

Front 45

Protein coats::
do what? (2)

Back 45

-shape vesicles
- and sure right stuff gets put inside

Front 46

::protein coats::
name three types

Back 46

1) clathrin
2) CopII
3) copI

Front 47

::protein coats::
describe functions of clathrin
copII
copI

Back 47

calthrin - trans golgi to lysosomes
COP I - golgi back to ER (betwen golgi )
Cop II - ER to golgi

Front 48

::protein coats::
apaptins

Back 48

between the protein coat and the cargo receptors -binds the coat to the receptors

Front 49

::protein coats::
does the protein coat get shed?

Back 49

yes

Front 50

::protein coats::
describe who clathrin works?

Back 50

1) proteins form a basklike network on surface, (shapes shape)
2)dynamin forms ring on neck of bud,
3) ring contracts and pinches off

Front 51

::protein coats::
What are dynamin?

Back 51

small GTP binding protein

Front 52

::protein coats::
transport signals?

Back 52

the coat receptors recongize them and bind to right cargo