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Topici 14: cell signaling & communication - Coggle Diagram
Topici 14: cell signaling & communication
signaling molecule will cause a chain rxn to stimulate responses
Endocrine Cell
give signaling molecule is conducted in body and then received by target cell
can be called hormone; if carried by blood vessel is can anywhere ol
target cell can be very far
Paracrine
Signaling cell send local mediator to close by cell by diffusion; & it ends up in the nearby cell receptors
target cell are very close
Neuronal
if signaling cell is a nerve cell its a neurotransmitter
Contact-dependent
the signaling cell and targeting cell need to have physical contact
signaling cells need to be able to distinguish each other
same signaling molecule will initiate different target cell responses; it depends on how the receptors are formed
mode of cellular communication
intracellular receptors= the receptors in located inside of cell
small hydrophobic signals can only do this bc they can cross ; but this is not that often
many of them are Tf; can cause gene expression change
Receptors have to be located in the plasma membrane bc the receptors can get in
called Cell surface receptors ; most common
more broad consequences; and are worse and more!
signal gets relayed into cell and this is called intracellular signaling molecules
signaling molecule called ligand
receptors are called cell surface receptors can be reconized by specific signaling molecules very good! like a key and a lock
GPCR (G-protein-coupled receptors)
associated w/ G-protien
when ligand is binds to GPCR
then the GCPR will bind to G protein
Then the G protein will be activated and then it will activate another anzyme
Enzyme coupled receptors
signal molecule will bind catalytic domain and activating it to enzyme or it will activate another enzyme down stream
G protein-coupled receptor
has 7 transmembrane segments & has external that will receive signaling molecule & has internal domain to recruit G-protein
GPCR pathway
signal will bind to receptor protein
then that will recruit G-protein
G-protein has 3 sub-unites
alpha
always will bind or to GDP or GDT protein
beta
gama
the GDP associated with G-protein will be replaced w/ GTP
so now GTP binds then G-protein will be dissociated
G-protein is activated form is alpha and will dissociate with the beta & beta will be
the G alpa will activate the down stream proteins
Formation of cyclic AMP
adrenaline will bind to the GPCR
the GPCR will get GTP alpha and will bind & activate target protein
then AC will use ATP to make cyclic AMP (secondary receptor) and that will activate another protein
the activated protein will active other things
the AC process
the ATP will use 2 p causing it to be cyclic AMP ( circular)
the enzyme cyclic AMP phosphodiesterase will degrade it by cutting the bond ( so no more circle) and AMP will not activate anything new
Breaking down of glucose level
important to maintain level of sugar in body
glycogen phosphorylase is what the enzyme that breaks down glycogen to glucose directly
glucose will be added and glycogen synthesis is the enzyme that will build glycogen (when blood sugar is low)
Glucagon or epinephrine (adrenaline) will initiate cellular responses through the GTP protein
activated PKA activate another enzyme call glycogen phosphoralase; that will eventually break down the glycogen to glucose