Signal receptors Flashcards
Hormones
produced by glands and act on external bodies
polypeptide growth facotors
act locally, in the area in which they are produced
Ionotropic receptors
‐ ionchannel (gate through which ions can transfer)
‐ receptor, binding spot for ligand.
‐ Synapsis in central nervous system
‐ Acetylcholine receptor; nicotine acetylcholine receptor
- bound by neurotransmitters (acetylochine - nicotonic)
- binding results in changes in ion transport
- extra cellular lignand binding domain, intercellular domain with enzymatic function
G protein coupled receptors
‐ Bound by hormones and slow transmission
‐ 7 transmembrane helices
‐ Bound to G‐proteins which hydrolyse guanosine triphosphate (GTP)
to GDP
Kinase receptors
‐ Extracellular ligand binding domain
‐ Intracellular domain with enzymatic function
‐ Transfer phosphate from ATP to target peptide
nuclear receptors
‐ Present in cytoplasm
‐ After binding of ligand migrate into cell nucleus and bind DNA
‐ Estrogen receptor (often high expressed in breast cancer)
- present in cytoplasm
- migrate after lignand binding to nucleus and and bind DNA
estrogen receptor signaling
protein molecule found inside cells that are targets for estrogen
agonist
activates receptor and results in a strong biological effect; the maximum
respons by a natural ligand = full agonist
partial agonist
activates the receptor but not to its fullest capacity, even not after
maximum binding
antagonist
binds but does not activate
inverse agonist
results after binding in opposite effect (for example instead of activation
it gives repression)
tyrosine kinase receptors
‐ Phosphorylate tyrosine residues in proteins (not serine/threonine)
‐ Transfer phosphate from ATP to target peptide
‐ Extracellular ligand binding domain
‐ Intracellular domain with enzymatic function
‐ critical role in the development and progression of many types of cancer
ErbB 1
Upon ligand binding the receptor undergoes a conformational change
The ligand binding domains are brought together and the cystein rich
region 1 is exposed
ErbB 2
no binding ligands, always in open configuration
ErbB 3
does not have tyrosine kinase domain
ErbBs
have different affinity for ligands
EGFR:EGFR
normal signal
ErbB3:ErbB3
no signal
ErbB4:ErbB4
normal signal
ErbB2:EGFR/ErbB3/ErbB4
strong signal
pertuzmab
antibody prevents dimerization by blocking CR1
cancer removal
‐ Surgical removal of tumors
‐ Chemotherapy: use cytostatic/cytotoxic drugs to remove tumors
‐ Radiotherapy: use radiation to remove tumors
targeted drugs
small organic molecules or biologicals, specific
active immunization
vaccination