Week 3 stuff Flashcards
(186 cards)
1
Q
Regulation of Microtubules
A
- Microtubule capping proteins
2. Microtubule severing proteins
2
Q
3 examples of microtubule severing proteins
A
katanin
spastin
fidgetin
3
Q
Microtubule functions (4)
A
- Cellular cytoskeleton
- intracellular transport
- cell division
- cilia
4
Q
Microtubules in cell division (3)
A
astral microtubules
kinetochore microtubules
centrospindle- overlapping attachment
5
Q
Domains of microtubules
A
alpha, beta, and gamma
6
Q
Plus end Subunit
A
beta
7
Q
minus end subunit
A
alpha
8
Q
GTP cap function
A
Stabilization
9
Q
Microtubule organizing center
A
centrosome
10
Q
Each centrosome contains 2 ___
A
centrioles
11
Q
Gamma tubulin forms _____ which binds to ____
A
rings outside of centriole
binds to minus ends
12
Q
Kinesin homodimer
A
Kinesin I
13
Q
Kinesin heterodimer
A
Kinesin II
14
Q
N terminus of kinesin
A
head domain
15
Q
C terminus of kinesin
A
tail domain
16
Q
for the tail domain to bind to cargo there is usually an associated ____
A
adaptor protein
17
Q
Energy used in kinesins
A
ATP
18
Q
Retrograde transport of ___ is essential for neuron proliferation
A
NGF
19
Q
In neuropathies, damage to the forward pathway is typically ____ than damages to the retrograde pathway
A
less severe
20
Q
Actin energy
A
ATP
21
Q
Minus end of actin has ____
A
open ATP pocket
22
Q
Actin step needed to grow
A
nucleation
23
Q
Actin filament structure and regulation (4)
A
- G actin concentration
- ADP to ATP exchange
- Capping
- Depolymerization/severing
24
Q
2 proteins that regulate nucleation
A
Formin (FH2)
Arp2/3
25
Arp2/3
branched
26
FH2
bundles
27
Arp2/3 and FH2 initiate nucleation by forming _____
pseudonucleation centers
28
Formin activation
small GTPases bind and activate
29
Actin roles in cell function
1. epithelial cell polarity
2. contraction
3. cell motility
4. cell division
30
Tight Junctions (TJ)
Separate apical and basolateral
31
Microvilli-> ___ dependent
FH2
32
Myosin involved in transport
Unconventional myosins
33
Cell motility: Arp2/3 complex regulates ____ formaion
lamellipodia
34
______ complex regulates lemellipodia formation
Arp2/3
35
Formins complex regulate ____ formation
filopodia
36
_____ regulate filopodia formation
Formins complex
37
Function of intermediate filaments
mechanical stability
38
receptor lipophilic
can be intracellular
39
receptor hydrophilic
has to be on cell surface
40
cell storage- lipophilic
NO
41
cell storage- hydrophilic
yes in vesicles
42
control of release lipophilic
only by synthesis
43
speed lipophilic
slow
44
speed hydrophilic
fast
45
Receptor types (4)
1. Ligand (or voltage) gated ion channels
2. GPCRs
3. Enzyme linked receptors
4. Nucleat receptors- TFs activated by cell penetrating signaling molecules
46
Second messenger examples (5)
1. Ca2+
2. cAMP
3. IP3
4. DAG
5. NO
47
cAMP is generated by ___
Adenylate cyclase (AC)
48
DAG are generated by ___
Phospholipase C (PLC)
49
NO generated by ____
NOS
50
Signaling proteins, activated by receptors or second messengers, can activate other signaling or effector proteins (including enzymes that generate second messengers) in a variety of ways. Including:
protein modification
| protein-protein binding
51
Amplification often depends on _____
how many downstream targets affected
| time it takes to terminate activity of a signaling molecule
52
signaling- Node
multiple input/multiple outputs
53
signaling- module
groups that function together
54
PDE5 function
breaks down cyclic GMP to GMP
55
PDE5 binding
catalytic site and noncatalytic site
cooperative binding
56
Protein that phosphorylates PDE5
PKG
57
PDE5 inhibitor
Sildenafil (Viagra)
| binds to catalytic site
58
Receptor tyrosine kinase activation is driven by _____
ligand mediated dimerization
59
Key downstream activation of EGFR
Ras
60
Active Ras
Ras-GTP
61
Inactive Ras
Ras GDP
62
GTP->GDP
GAP
63
GDP->GTP
GEF
64
Adaptor protein involved in Ras activation
Grb2
65
Domains of Grb2
SH2 and SH3 domains
66
SH2 domain of Grb2 binds____
Phospho-Tyr containing peptides
67
SH3 domain of Grb2 binds ____
Pro-containing peptides (Sos)
68
Ras GEF involved in Ras activation
Sos
69
Recruitment of Sos to the receptor ____
brings Sos in close proximity with Ras which is sequestered at the cell membrane
70
Two ways to inhibit EGFR
1. small molecule inhibitors that bind kinase domain
| 2. antibodies that bind extracellular domain
71
Example of antibody that blocks ligand binding site
cetuximab
72
Example of small molecule inhibitor of EGFR
getfitinib
73
What part of EGFR does getfitinib inhibit
ATP binding domain
74
Mutant EGFR is more active and more potently inhibited by ____
getfitinib
75
______ mutations in EGFR cause resistance to getfitinib
secondary
76
G-protein coupled receptors structure
7 helical transmembrane domains
Inside of cell:
i2 loop (bt 3 and 4)
i3 loop (5 and 6)
C-tail
77
____ % of all non antibiotic prescription drugs act through G protein coupled receptors
50%
78
G proteins that interact with GPCRs
Galpha
| Beta-Gamma
79
G alpha is inactive when bound to ___
GDP
80
G alpha is inactivated when bound to ___
GTP
81
Effector regulation following GPCR activation is mediated by ____
free alpha- GTP and beta-gamma subunits
82
bordello pertussis effect on GPCR
ribosylates Galpha near C terminal and locks it in the inactive state
83
bacteria that inactivates GPCR
bordello pertussis (whooping cough)
84
bacteria that activates GPCR
cholera
85
cholera effect on GPCR
ribosylates Galpha near GTP binding site to inhibit GTPase activity
86
Adrenergic receptors
Beta AR
| Alpha AR
87
Muscarinic receptors
m2 AchR and m3AchR
88
BetaAR and m2AchR- effects
cAMP production
BetaAR- stimulates
m2AchR- inhibits
89
alphaAR and m3 AchR- efects
stimulate Phospholipase C, Ca, and lipid signals
90
Agonists of beta adrenergic receptor
norepinephrine, epinephrine, or isoproterenol
91
Antagonists of beta adrenergic receptor
propranolol or metoprolol
92
cAMP->____->______
PKA->ca channels
93
Increase of calcium in hear causes_____
increased heart rate and contraction
94
Agonists of alpha adrenergic receptor
norepinephrine, epinephrine, or phenylephrine
95
Antagonists of alpha adrenergic receptor
prazosin
96
Agonist of m2 muscarinic cholinergic receptors
acetylcholine, Muscarine
97
Enzymes that catalyze cAMP to AMP
Phosphodiesterases
98
General PDE inhibitors
caffeine
| theophyline
99
cAMP specific PDE inhibitors
Milinirone PDE3
| Rolipram PDE4
100
Proteins associated with GPCR desensitizaiton
GRK
| Beta arrestin
101
After beta arrestin binds to GPCR ____
The receptor is internalized (endocytosed) and targeted for degradation in the lysosome
102
Beta arrestin b-arrestin also couples GPCRs to activation of additional downstream signaling pathways such as the ____ and ___ and ____ pathways
JNK
ERK
MAP kinase
103
More kinases or phosphatases?
Kinases
104
a kinase catalyzes what reaction?
nucleophilic attack of hydroxyl group onto gamma phosphate of an ATP molecule
105
Kinase domain
| where does atp bind?
small and large lobe
| cleft between lobes
106
Lobe of kinase that interacts with substrate
Large
107
closed conformation of kinase
glycine rich loop in the small lobe forces the gammaPhosphate of the ATP into the right position for phosphorylation (a fast reaction
108
Open conformation of kinase
glycine rich loop then allow exchange of the generated ADP for a new ATP (a slow reaction).
109
Which conformation of kinase is conserved? Why is this a problem?
open
| specific inhibitors
110
Important immunosupressants
calcineurin and mTOR inhibitors
111
Rate limiting step of GPCR activation
GDP dissociation
112
Beta adrenergic receptor G protein
Gs
113
Alpha adrenergic receptor G protein
Gq
114
m2 muscarinic cholergenic receptor G protein
Gi
115
m3 muscarinic receptor G protein
Gq
116
Desensitization of GPCRs (4 steps)
1. GRK interacts w/ beta gamma and phosphorylates receptor
2. Beta arrestin binds to phosphorylated receptor and inhibits alpha from rebinding
3. internalization
4. degradation by lysosome
117
Calcium sources (4)
1. ECF
2. ER/SR
3. Mitochondria
4. Nuclear envelope
118
Ca Ion channels- plasma membrane (2)
1. Voltage and ligand gated Ca channels
| 2. Store operated Ca channels (Orai1)
119
Ca ion channels ER/SR (2)
1. IP3 receptors
2. Ryanodine receptors
Ca moves from lumen to cytoplasm
120
Movement of Ca in mitochondria
depends on Ca gradient
| can be sink or source
121
Two types of Ca transporters
1. Ca pumps (ATP)
| 2. Na/Ca exchangers
122
Two types of Ca pumps
1. PMCA- Cyt-> extracellular space
| 2. SERCA- into lumen of ER
123
NCX exchange
3Na:1Ca
124
Cytoplasmic buffer
parvalbumin
125
Cytoplasmix buffers restrict the ____ and ____ spread of calcium and also serve as ____
spatial
temporal
temporary storage sites for calcium
126
Example of ER ca buffer
| ____ capacity _____ affinity
calsequestrin
| high, low
127
Ca effectors
1. membrane potential
2. PKC
3. Synaptotagmin
4. Calmodulin
128
function of synaptotagmin
Ca dependent fusion of synaptic vesicles
129
Binding of Ca causes ___ domains of ___ and _____ to associate with the plasma membrane
C2 domains
PKC
Synaptotagmin
130
Structure of calmodulin
4 EF-hand binding sites
| Each ca coordinated with 5 oxygens
131
Steps of helper T lymphocyte activation
1. antigen binds to TCR
2. Activate tyrosine kinase
3. Activate phospholipase C
4. PIP2-> IP3 and DAG
4. . Release ca, depleting ER stores
6. STIM1 senses depleted stores-> Orai1
7. Ca-calmodulin binds to calcineurin
8. Dephosphorylates NFAT
9. NFAT translocates to nucleus and promotes expression of IL-2 gene
132
True intestinal stem cell
Crypt base columnar cells (CBC)
133
Important gene expressed in CBCs
Lgr5
134
Niche for Lgr5 stem cells
Paneth cells
135
Epidermolysis bullosa is a defect in ____
Collagen 7
136
______ is a defect in collagen 7
Epidermolysis bullosa
137
Needed for conversion of somatic cells to ES-like stem cells
Reprogramming factors
138
4 reprogramming factors
1. Oct3/4
2. Sox2
3. c-Myc
4. Klf4
139
New therapies in cancer treatment
Directed against cancer stem cells
140
PSA in prostate cancer
Prostate specific antigen
| lower levels are better
141
Methods of hormone therapy in prostate cancer
1. Surgical bilateral orchiectomy
2. GNRH agonis
3. Anti- androgen
142
Hormone refractory prostate cancer
Disease progression with a testosterone of less than 50 ng.dl
143
For most mammalian cell types, adhesion to ______ or the ____ is critical for cell survival
other cells
| Extracellular matric
144
Cell adhesion is ___
selective
145
The relative amount of ECM in different tissues ____ , from connective tissues, where the ECM may occupy_____ to brain, where it is ________.
Varies greatly
the bulk of the volume
a very minor component only
146
Functions of the ECM
1. scaffold for cells
| 2. regulation of various cell functions
147
In connective tissues, the ECM macromolecules are synthesized and secreted primarily by______ or ______, such as ______ (in cartilage) or _______ (in bone).
Fibroblasts
specialized members of the fibroblast family
chondroblasts
osteoblasts
148
4 major classes of molecules in ECM
- glucosaminoglycans (GAGs), linked to proteins called proteo glycans
- fibrous proteins (collagen, elastin)
- multidomain adaptor proteins (fibronectin, Laminin)
- water and many solutes
149
Proteoglycans form ___
highly hydrated gel in which fibrous and multidomain proteins are embedded
150
Fibrous proteins give ECM ___
mechanical properties
151
Structure of GAGs
unbranched polysachharide composed of disaccharide repeats
- one is always amino sugar, usually sulfated
- the other is typically uronic acid
152
GAGs charge
negative
| Gives capacity to be highly hydrated
153
The "core protein" of proteoglycans has attached to ___ special ______, and these serve as the _____ for polysaccharide assembly
serines
link tetrasaccharides
primers
154
Some PGs are membrane-bound molecules, anchored via a ______ or linked via a ______
transmembrane core protein tail
| GPI anchor
155
Collagen I
most common form
| abundant in connective tissues
156
Collagen IV
characteristic of basal lamina
157
Elastin
Provides elasticity
158
Multidomain adaptor protein
act as binding sites for other matrix macromolecules and for adhesion molecules on the surfaces of cells.
159
Fibronectin structure
large, dimeric glycoprotein
| large subunits linked together by disulfide bonds
160
Type III fibronectin repeat domain binds to ___
integrins
161
Binding sequence of Type III fibronectin repeats
Arg-Gly-Asp
162
secreted fibronectin assembles in the ECM into highly insoluble _____
fibronectin fibrils
163
Three subunits of laminin
alpha, beta, gamma
164
Lamina is found in ___
basal lamina only
165
Laminins, like fibronectins, have numerous binding sites for cells (integrins; see below) and other _____ that link them to ____
ECM proteins
| Collagen IV
166
Proteins that regulate the ECM
Proteases
167
Proteases in ECM
```
matrix metalloproteases (MMP)
can be selective or promiscuous
```
168
Extracellular protease activity is particularly important in _____ and in __________
tissue remodelind in development
| cell invasion of tissues
169
When bound to a ligand, CAMs signal their engagement via _____, thus affecting _____
conformational change to the cell interior
| cell function
170
3 most abundant classes of CAMS
1. Cadherins
2. IgSF CAMS
3. Integrins
171
Cadherin binding is ___ dependent
Ca2+
172
Cadherins bind to other cells via cadherins on the juxtaposed cell surface (homophilic binding) in a________
zipper like fashion
173
Cadherin structure
single pass transmembrane glycoproteins that operate as homodimers
174
IgSF members do not form ____, and binding does not require ____.
dimers
| Ca2+
175
2 homophilic CAMs
| 1 heterophilic CAM
Homo- cadherin, IgSF CAM
| hetero- integrins
176
Structure of integrins
alpha/beta heterodimers
| both participate in ligand binding
177
Typical ligands of integrins
laminin
fibronectin
collagen
Many involving RGD sequence
178
Cytoskeletal link of CAMs
acin-binding proteins
| catenins
179
In addition to providing the cytoskeletal link, CAM-associated proteins also are involved in the ____, _____, and in _____
regulation of adhesion
control of actin polymerization
cell signaling
180
Fibronectin null mutant mice are ______
early embryonic lethal
181
Some laminin mutations have been linked to _____ (glomerular filtration defect) and to _______ problems in children
nephrotic syndrome
| neuromuscular junction/muscle innervation problems
182
Loss-of-function mutations of matrix metalloproteases (MMP) 2 or 13 cause
inherited osteolysis/arthritis syndromes and bone dysplasias
183
Overexpression of some MMPs, specifically MMP_, MMP_ and MMP__, correlates
2,9,14
| high invasiveness and poor prognosis in many cancers
184
Two types of leukocyte adhesion deficiencies
Type I- integrin
| Type II- selectin
185
One of the early signs of carcinogenesis is a change in CAM(s). This is accompanied by
(and may be the reason for) perturbed_________
cell polarity and cytoarchitecture
186
Cadherin down-regulation appears to be a prerequisite for the dispersal of ________
endothelium derived cancer cells
