Cell signalling Flashcards
signalling pathway converting extracellular signal to response
signal reception transduction amplification response
how can activity of proteins be altered?
- changing level of protein
- changing activity of fixed amount of protein
conformational change
covalent modification
kinases
enzymes that add phosphate groups
phosphatases
enzymes that remove phosphate groups
gap junction
between neighbouring cells
2 hemichannels join end to end = connexion
2 connexions = gap junction channel
contact dependent
molecules not secreted, bound to membrane
autocrine
cell able t bind to signals it secretes
self signalling
paracrine
signalling using local mediations
nuclear hormone receptors
undergo conformational change in response to ligand binding
receptor ligand complex regulates target gene transcription
no receptor = no response
ion channel coupled receptors (ligand gated ion channels)
convert chem signals to elec signals
binding of ligand induces conformational change in receptor
G protein coupled receptors
G proteins are transducers in signalling pathway
transduce signals by binding to other target proteins on the plasma membrane
bind to GDP or GTP
as long as receptor is activated this will interact and activate other g proteins
turn themselves off by GTP hydrolysis
trimeric
transduce signals from GP linked receptors
3 subunits
monomeric
transduce signals from enzyme linked receptors
alpha subunit of trimeric g protein
GTPase binds GDP in resting state
2 key proteins activated by trimeric g proteins
Adenyl cyclase
cAMP (2nd messenger)
