Exam III: Chapter 16

Cell Signaling Textbook + Extras

signal transduction

taking one signal and making it into another

signaling cell

sends out a signal

extracellular signal molecule

how a signal is sent between cells

* proteins
* amino acids
* gas
* steroids
* fatty acids

target cell

cell that receives the signal

receptors

recognize a signal and cause a reaction

intracellular signal molecule

how signals are sent within a cell and leads to a change in cell behavior

cell signaling

signal reception + transduction

hormone

actual signal sent to whole body through blood or sap

endocrine cells

make hormones in animals

endocrine signaling

blanket message to who body through blood or sap via hormone

paracrine signaling

type of signal that is localized to a group of cells and travels through extracellular fluid

local mediator

signal that only work on neighboring cells- short range

autocrine signaling

when cells send signals to others in a localized area. must be the same type of cell and the original cell can receive its own signal

* used in cancer

neuronal signaling

sending message through neurons/synapses and is long distance

neurotransmitter

signal molecule for neuronal signalling

contact-dependent signaling

cells touch each other and send a message directly to one another. signal is in membrane and is touched to receptor

receptor

protein that responds to a certain signal

* extracellular receptor: very large or phillic signal
* intracellular “: small or phobic

effector proteins

execute how a certain cell will respond to a signal

transmembrane receptor

senses a signal outside the cell and sends it to inside the cell in a new form

* can trigger a cascade of signals within the cell

intracellular signaling pathway

many proteins that work together within a cell to send a message to a specific location

amplify

make a signal more prominent

relay

sending the signal to the next protein

integrate

combining multiple signals to only send out one

distribute

one protein sending a signal to multiple destinations

feedback

controlling what happens in the steps before them by sending a signal

feedback regulation

step in the signal pathway controlling cellular action by promoting or minimizing a signal

positive feedback

response from within pathway that increases activity on the pathway

* switch

negative feedback

response from within pathway that decreases activity on the pathway

* toggle

molecular switch

signal put the protein from inactive to active conformation or vice versa

* need to be actively switched off
* controlled by phosphorylation or binding

protein kinase

puts P group on DP

protein phosphatase

takes P group off TP

phosphorylation cascade

kinases activating each other

serine kinase

phosphorylate serine proteins

threonine kinase

phosphorylate threonine proteins

tyrosine kinase

phosphorylate tyrosine proteins

GTP binding protein

protein active or inactive dependent on if GDP or GTP bound

trimeric GTP-binding proteins

send message from G-protein-coupled receptors

monomeric GTPase

\

guanine nucleotide exchange factors (GEF)

help take a GDP and replace with GTP

GTPase activating proteins (GAP)

help swap GTP for GDP

RTK

receptor tyrosine kinase

enzyme coupled receptor

transmembrane protein with receptor on the extracellular side and enzymatic tails on the cytosolic side

tyrosine phosphatase

removes RTK’s phosphate groups to deactivate

Ras

GTP binding protein with one phospholipid tail hooked in the plasma membrane

Ras-GAP

helps Ras go from GTP to GDP

GEF

helps Ras go from GDP to GTP

MAP kinase kinase kinase

puts phosphate group on MAP kinase kinase

MAP kinase kinase

puts phosphate groups on MAP kinase

MAP kinase

phosphorylates many types of proteins and transcription factors

MAP

signals for cell division/replication

PI 3-kinase

will phosphorylate inositol phospholipid

protein kinase B

prevents Bad molecule from signaling

AKT

another name for PKB

Tor

proteins which signals to prevent protein degradation and encourage protein synthesis

Notch

protein that signals for cell to become neural cell

Delta

signal that attaches to Notch

signal transduction

1) reception

2) primary transduction

3) relay

4) amplification

5) divergence

receptor

what a signal will attach to

hydrophobic signaling

signaling using fatty acids, gas, steroid, cholesterol based

eicosanoid

small fatty acid signals for pain

* cause smooth muscle contraction, inflammation, platelets
* are prostaglandin
* are leukotrienes

arachidonic acid

20 C phospholipid tail

* ecoisinoid’s linear precursor

cycloxygenase

folds arachidonic acid into eicosanoids

COX1

constitutive enzyme that acts as cycloxygenase

COX2

inducible enzyme that acts as cycloxygenase 

PGG2 and PGH2

two eicosanoids that can be blocked with asprisin

aspirin

drug that prevents cycloygenase activity

leukotriene

lipid that makes inflammation

lipoxygenase

fold arachidonic acid into leukotrienes

leukotriene

eicosanoid responsible for inflammation

prostaglandin

eicosanoid that increases membrane permeability

acetylcholine

neurotransmitter that initiates:

* saliva production
* skeletal contraction
* decreased heart rate

endothelial

blood vessel cell

acetylcholine receptor

where acetylcholine binds to on endothelial cell membrane; initiates Ca2+ influx

Ca2+

cofactor for NO synthase

arginine

NO is created from this amino acid via NO synthase

soluble guanyl cyclase

takes NO and makes cGMP from GTP

* i.e. SGC

cGMP

activates protein kinase G (PKG)  

protein kinase G

phosphorylates myosin light chain kinase (MLCK)

MLCK

causes smooth muscle contraction

* can be phosphorylated by PKG to inactivate

MLCP

causes smooth muscle relaxation

* can be activated by PKG

smooth muscle relaxation

following factors all allow for blood vessel dilation and ….

* deactivated MLCK
* activated MLCP
* open Ca2+ channel
* open K+ channel

phosphodiesterase

causes cGMP breakdown to deactivate PKG

viagra

signal recognition particle and competitive inhibitor of phosphodiesterase

steroid

cholesterol derivative hormone

* cortisol

gene transactivation

activating gene transcription based on signal


1. cortisol diffuses through plasma membrane
2. cortisol binds to intracellular receptor protein
3. activated complex enters nucleus
4. complex attaches at target gene to start transcription

intracellular receptor protein

binds to cortisol to enter the nucleus

NO pathway

1. acetylcholine binds to Ac receptor in endothelial
2. Ca2+ influx
3. NO synthase activated
4. arginine made into NO
5. NO diffuses to smooth muscle cell
6. NO activates guanylyl cyclase (SGC)
7. GTP made into cGMP
8. cGMP binds to PKG


1. MLCK deactivated
2. MLCP activated
3. Ca2+ increases
4. K+ increases
9. muscle relaxation

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eicosanoid pathway

1. phospholipase A2 makes arachadonic acid
2. 2 pathways


1. COX1/COX2 fold chain into prostaglandin
2. lipoxygenase folds chain into leukotriene

\

phospholipase A2

cuts out arachidonic acids from phospholipid

G protein coupled receptor

7 pass protein


1. signal binds to receptor
2. conformation change in alpha, beta, gamma subunits
3. GDP replaced by GTP with GEF’s help


1. GTP bound to alpha subunit
4. activated g-protein target protein
5. GAP and g-protein alpha subunit cut GTP into GDP

arrestin

adaptin that binds to phosphorylated g-protein to prevent function

kinase

phosphorylates

glycogen

… breakdown


1. epinephrine binds to GPCR
2. adenylyl cyclase activated
3. ATP made into cAMP
4. cAMP activates PKA
5. PKA activates glycogen phosphorylase with ATP
6. glycogen phosphorylase breaks glycogen into glucose

\

1. activates PKA inhibits glycogen synthase alpha
2. synthase alpha becomes synthase beta

protein kinase a

PKA = phosphorylase kinase

* ATP to ADP
* 4 cAMP: 2 subunits

CREB

PKA is also used for … activation


1. GPCR activates adenylyl cyclase
2. adenylyl cyclase takes ATP to cAMP
3. cAMP activates PKA
4. PKA moves to nucelus
5. PKA activates transcription regulator
6. transcription regulator allows DNA transcription

deamplification

making a signal smaller

CREB

transcription factor

calmodulin

cofactor with Ca2+ that is always in the cytosol

* together activate caM-kinase
* goes onto phosphorylate others

Ca2+ channel

can open …


1. signal binds to GPCR
2. phospholipase C activated
3. cleaves IP3 from diacylglycerol


1. IP3 binds and opens Ca2+ channel
2. diacylglycerol docks PKC


1. Ca2+ binds to PKC to activate

protein kinase c

PKC

* phosphorylates serines and threonine