11.2 plasma membrane receptor Flashcards
3 main types
G protein-coupled reactions
-receptor tyrosine kinases
ion channel receptors
G protein coupled reactions
-works with G protein to bind GTP (an energy rich molecule)
G protein coupled reactions structure
ALL have 7 alpha helixes spanning the membrane
when did G protein coupled reactions evolve
really early
–because the receptors are similar to systems in vision. smell, embryonic development…etc.
G protein coupled reactions disease
they relate to a lot of disease
-60% of medicines today are exerting influence on G pathways
how does G protein coupled reactions work
1) G receptor gets signal molecule and changes shape
2) the receptor accepts/ binds to an in active G protein with GDP and then GTP replaces GDP and the G protein is activated
3) g protein disassociates and binds to an enzyme that changes shape to start the next step in to the cellular response
receptor tyrosine kinase
- class of plasma membrane receptors with enzymatic activity
- they attach phosphates to tyrosine
kinase:
an enzyme that catalyzes the transfer of phosphate groups
what differs receptor tyrosine kinase to G couples
they can activate so many pathways at once
they can cause cancer
receptor tyrosine kinase structure
alpha helix + multiple tyrosines + ligand binding site
how does receptor tyrosine kinase work
when ligands bind to binding site, 2 polypeptides aggregate together and form a dimer
- -the dimer activates tyrosine kinase and each tyrosine kinase adds a phosphate from atp to the tail of the other polypeptide
- -other proteins can bind to it to be activated to produce cellular responses.
Ligand gated ion channel
Type of membrane receptor with a region like a gate that controls male sé characteristics
How does it works
When a signal molecule bind to the gate, it opens
Voltage gated ion channels
Controlled by electrical signals rather than molecule
