Lecture 4 Flashcards
What are the largest family of receptors and how much of the human genome do they account for?
GPCR
2% of the human genome
What are the two important features that all tyrosine kinase receptors have?
- all have extracellular binding domain
- inside the cell there’s a kinase domain
what is an example of class 1
EGF
what is an example of class 2
insulin receptors
what is an example of class 3
FGF
what does insulin do?
stimulates the uptake of glucose in the muscle cells when blood glucose level are high
what kind of receptor is the insulin receptor
a dimer
describe the basic structure of insulin
large, 2 chain hormone
A and B chain
true or false; beta subunit of insulin receptor spans the cell membrane and is inside the cell
true
describe the steps of how insulin receptor works?
- ) insulin binds to the alpha subunit
- ) this triggers a conformational change in the receptor activating the kinase domain of the B-receptor
- ) the activated kinase domain, will undergo auto-phosphorylation of the tyrosine domains
- ) receptor then phosphorylates tyrosine residues on target proteins
- ) these are known as IRS (insulin receptor substrates); considered as second messengers
how does insulin acting in the muscle stimulate glucose uptake
GLUT-4 is moved to the cell surface (translocation)
what are the similarities between RTKs and GPCRs
- both types of receptors are activated by hormones
- both types of receptor span the membrane and undergo a conformational change when the hormone binds
- second messengers are involved in the signalling process for both types of receptors
- phosphorylation events are important
What are the differences between GPCRs and RTKs
- RTK contains kinases as part of receptor but GPCRs do not
- GPCRs use G protein but RTKs do not
- the structures of the receptors are different
