Second Messenger Signalling Flashcards
What two receptor classes gate ion channels indirectly?
G-protein coupled receptors
Receptor and non-receptor tyrosine kinases
What does second-messenger signaling allow?
Neurotransmitter binding to result in a neuronal adaptation due to stream alterations in protein expression
What do G proteins detect?
Presence of activated receptors and amplify signal by altering activity of appropriate effector enzymes and channels
What are 3 types of second messengers?
Hydrophobic molecules eg DAG
Hydrophilic molecules eg. cAMP
Gases eg NO
What does a G-protein coupled receptor consist of?
Single subunit with 7 membrane spanning regions
What does binding of a transmitter to a G-protein coupled receptor activate?
Transducing G-protein that activates a primary effector enzyme
What does dimer G (beta gamma) interact with?
Alpha subunit in the presence of GDP
What happens when a signal interacts with the G protein coupled receptor?
GDRP is exchanged for GTP which dissociates inactive heterotrimeric G protein generating G alpha GTP and G beta gamma
What does the GTPase activity do?
Protein hydrolyses its own GTP converting it back into GDP
What happens when the Gs is activated?
Exchanges its GDP for GTP -> alpha subunit dissociates
What happens when the alpha subunit dissociates?
Exposing a binding site for adenylyl cyclase
What does adenylyl cyclase catalyse?
Conversion of ATP to cAMP
What is the major target action of cAMP?
cAMP dependent protein kinase
