7: Cell Communication 1 Flashcards
What allows communication between cells?
Gap junctions
What are gap junctions made up of?
Connexin proteins
- Gated by Ca2+, voltage and membrane potential, also phosphorylation
- Referred to as ‘electrical synapses’
What are the two main classes of receptor and messenger/ligand?
- Water soluble chemical messengers
- Lipid-soluble chemical messengers
How does water-soluble chemical messengers work?
signals can’t diffuse through the plasma membrane, so they bind to plasma membrane receptors. Activate specific cellular signalling
How do lipid-soluble chemical messengers work?
Diffuse through the plasma membrane and bind intracellular receptors located in the cytoplasm or nucleus. Alters transcription
What are the 4 types of plasma membrane receptors
- Ion channel linked receptors aka ionotropic receptors
- G protein coupled receptors (GPCR) aka metabotropic
- Enzyme linked receptors
- Regulated intramembrane proteolysis
Draw/label an ion channel linked/ionotropic receptor
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Draw/label a G protein coupled receptor/metabotropic receptor
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Draw/label an enzyme linked receptor
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What are some chemical messengers/signals for ion channel linked receptors
Neurotransmitters (acetylcholine, glycine, GABA, glutamate), purines, serotonin
What are some signals for enzyme linked receptors
Nerve growth factor, growth hormone, insulin
What are some signals for regulated membrane proteolysis
Amyloid precursor protien, Notch
Describe the G protein signalling pathway (diagrams will help as well)
- Ligands binds to receptor, which activates it
- Receptor interacts with the G protein to promote a conformational change and the exchange of GDP for GTP
GEFs facilitate the dissociation of GDP and the binding of GTP - G protein dissociates from the receptor
- alpha GTP and beta-gamma subunits dissociate
(look though slides)
What are the two ways that ion channels are able to be activated
Indirectly via GPCRs or
Directly by neurotransmitters
Describe how ion channels can be activated indirectly via GPCR
- Neurotransmitter binds
- G protein is activated
- G protein subunits or intracelular messengers modulate ion channels
- Ion channel opens
- Ions flow across membranes
(look through slides for full detail)