Study BMB 464 Exam 1 Nuclear Import Flash Cards

 
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BMB 464 Exam 1 Nuclear Import

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fluoresence from which fluorophore is actually being measured?
NBD (the green is being measured)
Which fluorophore does the quenching and which is quenched?
-NBD is quenched
two fluorophores used to do FRET
NBD (green)
rhodamine (yellow)
FRET
-florescence resonance energy transfer
-
SNAP receptor
SNARE
-required for fusion
-3 proteins total: 1 in vesicle, 2 in target
SNARE docking
-tight/stable complex
-4 coiled-coils helix bundles
-where E for fusion comes from
The role of SNAP and NSF is thought to involve dissociation of this complex after
fusion- where does the energy the use to dissociate the complex come from?
ATP
Name the t-SNAREs that act in synaptic vesicle fusion.
the t-SNAREs syntaxin and Snap25
t-SNARE protein info
2 polypeptides form the t-SNARE.
Name the v-SNARE that acts in synaptic vesicle fusion.
synaptobrevin
The SNARE hypothesis is...
...an attempt to explain how specificity of docking and fusion is determined
The luminal space is equivalent to the
_______________.
extracellular space
Describe in detail a cycle of nuclear import of a protein with a classical NLS, including
how Ran plays a role.
yup
If a protein wants to know whether it is in the nucleus what does it need to recognize?
Ran GTP
What is the GAP specific for Ran?
Rna1p in the cytosol
What is the GEF specific for Ran? Where is it? What does it bind? Why is this important?
Rcc1 in the nucleus
Why is it typically GTP that is bound after the GEF interacts with Ran?
REPLACES with GTP
Understand that the transition from the GTP-bound to GDP-bound state happens
as the result of the enzymatic activity of the G protein (stimulated by the GAP)
In contrast, understand that the transition from the GDP-bound to the GTPbound
state happens as the result of exchange in binding one molecule for another.
yup
What is a GAP? Do they "turn on" or "turn off" G proteins?
GTPase activating
protein; turns off
What is a GEF? Do they "turn on" or "turn off" G proteins?
Guanine nucleotide
exchange factor; turns on
Is the GDP or GTP bound form the active state?
GTP
RanGTP is present in the nucleus due to action of ____________.
GEF called RCC1
which component of the dimeric receptor (alpha/beta) binds the nucleoporin protein in the nuclear
pore?
beta
which component of the dimeric (alpha/beta) receptor binds the NLS?
alpha
transfer of a NLS to a gold bead is an experiment that can demonstrate...
... that a NLS is sufficient for nuclear localization
mutation of a NLS can demonstrate...
...that the NLS is necessary for nuclear localization
what does a classical NLS look like?
-4 to 8aas
-rich in positively charged aas
-can be situated anywhere in
the protein
What proteins are capable of crossing the nuclear membranes?
only proteins with the appropriate nuclear localization signal or a small protein, less than 60kD can freely diffuse
how big are proteins to cross the nuclear membrane?
<60kDa
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