CSF (Cell Signalling) Flashcards
What are the two types of local signals?
Paracrine or synaptic
What is an example of a paracrine signal?
Growth factors released (eg. For blood clotting)
What is an example of synaptic signalling?
Neurotransmitters are released and bind to receptors in the target cell, causing an ion channel to open.
What allows temporal and spatial control over the cell signalling process?
Lock and key. Only certain cells at certain times will have particular receptors.
Intracellular receptors
Primary messenger is hydrophobic or small. Cytoplasm / Cytosol. Sex hormones.
Membrane-bound /
Cell surface receptors
Primary messenger is generally hydrophilic or large. Need help to cross PM. GPCR, Tyrosine Kinase, Ligand-gated ion channel.
What are GPCRs?
G-Protein Couple Receptors.
Transmembrane proteins that pass the PM 7 times. Many diff ligands. Diverse functions.
What causes the G-protein to be released from the enzyme after activating it?
It has GTP-ase activity, releasing it from the enzyme, returning to resting point.
Receptor definition
A molecule/protein which responds to a specific ligand.
Ligand definition
A signalling molecule that binds specifically to another protein.
Ion channel definition
Membrane protein through which specific ions can travel.
Ion channel receptor definition
Membrane protein through which specific ions can travel, in response to ligand binding (also known as ionotropic receptors.)
Example of ligand ion channels in use
Released neurotransmitters bind as ligands to ion channels on target cells to propagate action potentials.
What are protein kinases?
Enzymes that transfer a phosphate group from ATP to another protein. Typically, this activates the protein.
How does a phosphorylation cascade work?
Series of protein kinases add a phosphate to the next kinase. Phosphatases enzymes dephosphorylate rendering the protein inactive but recyclable.
