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BIOL 2021 Lecture Notes - Lecture 6: Nuclear Localization Sequence, Nuclear Export Signal, Nuclear Pore

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turquoisehamster570

9 Feb 2018

School

York University

Department

Course

Professor

Patricia Lakin- Thomas

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Document Summary

Gated transport: active transport through pore requires: sorting signal, 2) receptor, 3) energy source, sorting signal, called a nuclear localization signal (nls) for import. Import receptors are soluble proteins, bind to nucleoporins and nls of cargo (something that"s being carried). They also have domains to recognize nucleoporins, to carry the cargo: different nuclear import receptors bind different nuclear localization signals and thereby different cargo proteins. Some cargo proteins require an adaptor protein to bind to their nuclear import receptor. The adaptors are structurally related to nuclear import receptors and recognize nuclear localization signals on cargo proteins. They also contain a nuclear localization signal that binds them to an import receptor, but this signal only becomes exposed when they are loaded with a cargo protein: energy source = gtp hydrolysis. Fig 12-12 ran gap and gef: gtpase = protein that binds and hydrolyzes gtp, ran-gtpase = for nuclear import and export, carries receptors out of nucleus.

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Related Questions

True or False? True False
1. Proteins rapidly pass artificial membrane (liposome).--------------------------------------------------------------------------------------( ) ( )
2. Amphiphatic detergent such as SDS spontaneously forms bilayer inwater. ------------------------------------------------------------( ) ( )
3. Cholesterol does have a hydrophilic head and hydrophobic tail.-------------------------------------------------------------------------( ) ( )
4. Fat molecules are one of the major components of the plasmamembrane.------------------------------------------------------------- ( ) ()
5. Phospholipid molecules such as phosphatidylcholine spontaneouslyform bilayer. ----------------------------------------------------( ) ( )
6. Flippase facilitates lateral movement of phospholipids withinthe plane of the membrane.----------------------------------------- ( ) ( )
7. Glycolipids make bilayer less permeable to small water solublemolecules.----------------------------------------------------------- ( ) ()
8. Membrane inner leaflet is enriched with phosphatidylcholine,Sphingomyelin, and Glycolipid. -----------------------------------( ) ( )
9. Plasma membrane proteins can have an enzyme activity.--------------------------------------------------------------------------------( ) ( )
10. A single pass membrane protein must have an amphiphatic alphahelix.-------------------------------------------------------------- ( )( )
11. Plasma membrane proteins can be linked to a lipid molecule atthe outer leaflet of the plasma membrane. --------------------- ( )( )
12. The lateral motility of membrane proteins can be restricted bytight junctions.------------------------------------------------------ ( ) ()
13. Channel proteins have specific binding sites for ions and thusslower than carrier proteins.--------------------------------------- ( ) ( )
14. An antiport would function as a symport if its orientation inthe membrane were reversed. ---------------------------------------( ) ( )
15. A transmembrane pore can be formed by multiple amphipathicalpha helices. ----------------------------------------- ( ) ()
16. Porin proteins form water-filled channels in the outer membraneof a bacterium and are mostly composed of beta sheets. ---- ( ) ()
17. Glucose uniporters localize at the apical side of theintestinal epithelium.------------------------------------------------------------ ( ) ()
18. GAP junction is a selective pore for anions.-----------------------------------------------------------------------------------------------( ) ( )
19. A voltage-gated Na+ channel adopts only two conformationstates: open and closed.----------------------------------------------- ( ) ( )
20. Voltage gated K+ channel opens faster than the Voltage gatedNa+ channels.-------------------------------------------------------- ( ) ()
21. Opening of chloride channel at the synapse will help to fire anaction potential.------------------------------------------------------ ( ) ()
22. The nuclear pore complex forms a gate through which moleculespass the nucleus uni-directionally. -------------------- ( ) ()
23. A completely folded protein is imported into a mitochondrionthrough a large non-selective pore.--------------------------------- ( ) ( )
24. ER signal sequence contains multiple lysine and arginineresidues.----------------------------------------------------------------------( ) ( )
25. The plasma membrane is a sorting station of inward endocyticpathway.---------------------------------------------------------------- () ( )
26. The trans Golgi functions as a sorting station of outwardsecretory pathway.----------------------------------------------------------- ( ) ()
27. Vesicles budding from ER are coated with Clathrin.----------------------------------------------------------------------------------------( ) ( )
28. RabGTPases and tethering proteins are the major specificitydeterminant of vesicle transport system. --------------------------( ) ( )
29. v-SNARE proteins are one of the tethering proteins.------------------------------------------------------------------------------------( ) ( )
30. In secretory cells, the constitutive and regulatory pathways ofexocytosis diverge at the cis Golgi network. ------------------ ( )( )
31. Many proteins are posttranslationally glycosylated at tyrosineresidues in the ER.------------------------------------------------- ( ) ( )
32. Cells import LDL molecules exclusively through pinocytosis.-------------------------------------------------------------------------( ) ( )
33. Cells recycle LDL receptors from lysosome to the plasmamembrane.----------------------------------------------------------------- () ( )
34. Phagosomes fuse with late endosome.------------------------------------------------------------------------------------------------------( ) ( )
35. Small vesicles from ER near the plasma membrane can fuse withthe plasma membrane upon bypassing Golgi apparatus. -- ( ) ()
36. If a Sec mutant showed an accumulation of newly synthesizedproteins at ER,
then the Sec gene is likely a component of vesicle-buddingmachinery of trans-Golgi network.------------------------------------ ( ) ( )
37. A signal recognition particle is a single pass trans-membraneprotein of the ER membrane.---------------------------------------- ( ) ( )
38. Typical animals cells display higher levels of intracellularsodium than extracellular compartments.------------------------------ ( ) ( )
39. Typical animals cells display higher levels of intracellularchloride than extracellular compartments.----------------------------- ( ) ( )
40. The Na-K Pump is a GTPase that can adopt active and inactiveconformational states.----------------------------------------------- ( ) ( )
1. Phospholipase
C-Â-Ã
produces
phosphatidylinositol
3,4,5-Â-trisphosphate
and
diacylglycerol.
(
)
(
)
2. PDGF
activates
GPCR.
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(
)
(
)
3. Rho
is
an
example
of
heterotrimeric
G
proteins.
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(
)
(
)
4. All
members
of
the
G
protein
coupled
receptors
interact
with
small
GTPase
Ras.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
5. Adrenaline
is
an
example
of
the
ligands
for
the
RPTK
family.
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(
)
(
)
6. Ras
GEF
activates
RPTK.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
7. PH
domain
containing
proteins
bind
to
activated
EGFR.
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(
)
(
)
8. Ligands
for
GPCR
proteins
induce
dimerization
of
the
receptor.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
9. Grb2
is
an
adaptor
protein
that
binds
to
a
phospho-Â-tyrosine
residue
of
activated
RPTK
through
a
PH
domain.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
10. When
a
cell
is
expressing
a
large
number
of
dominant
negative
EGFR
proteins,
an
introduction
of
a
constitutively
active
Ras
mutant
will
allow
EGF
signaling.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
11. PI3K
generates
phosphatidylinositol
3,4,5-Â-trisphosphate
from
IP3.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
12. Calcium
inhibits
PKC.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â----Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
13. cAMP
activates
PKA.
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(
)
(
)
14. The
MAP
kinase
ERK
inhibits
MAP
kinase
kinases.
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(
)
(
)
15. cAMP
is
an
example
of
a
first
messenger.
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(
)
(
)
16. All
7-Â-Transmembrane
receptors
are
G
Protein
Coupled
Receptors.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
17. Both
Ga
and
GÃ
subunits
of
the
heterotrimeric
G
protein
can
mediate
GPCR
signaling.
-Â--Â--Â-
(
)
(
)
18. Both
Ga
and
GÃ
subunits
of
the
heterotrimeric
G
protein
have
GTPase
activity.
-Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â--Â-
(
)
(
)
19. The
Gas
subunit
of
the
heterotrimeric
G
protein
suppresses
the
function
of
Adenylyl
cylase.
(
)
(