enzyme linked

Question 1

the function of receptor tyrosine kinase

Answer 1

they transfer phosphorus from ATP to intracellular proteins to activate them

Question 2

what happens when a ligand binds to its binding site on a RTK

Answer 2

neighbouring RTKs come together to form a dimer

tyrosine regions are then cross phosphorylated to fully activate it

Question 3

what happens once RTK is activated

Answer 3

adapter protein attaches to the tyrosine region, RAS protein is activated and imitates MAP protein kinase cascade

Question 4

what does MAP protein kinase do

Answer 4

phosphorylates and activates transcription factors

Question 5

how does cytokine signalling differ from standard RTK mechanism

Answer 5

1. cytokine binds and 2 neighbouring receptors dimerise as in RTK
2. JAK kinase is activated and it phosphorylates the other tyrosine sites
3. STAT proteins are attracted to the phosphorylated cytokine receptor, they are phosphorylated and dimerised
4. STAT proteins migrate to nucleus to initiate transcription

Question 6

the 4 kinds of enzyme linked receptors

Answer 6

receptor tyrosine kinase
RTK associated
serine/threonine kinases
receptor gunaylyl cyclayses

Question 7

mechanism of serine/threonine kinases

Answer 7

ligand binds to type 2 receptor
type 2 receptor phosphorylates type 1 receptor
activated type 1 receptor recruits SMAD protein
SMAD is phosphorylated, dimerised and moves to nucleus to mediate transcription

Question 8

what family of ligands use serine/threonine kinases for signalling

Answer 8

transforming growth factor beta

Question 9

purpose of guanylyl cyclase

Answer 9

converts GTP to cyclic GMP

Question 10

what does cGMP do

Answer 10

it activates PKG