Tyrosine Kinase Signalling Pathways Flashcards
What receptors do hydrophilic molecules interact with?
Hydrophilic molecules cannot pass through membranes, so have to interact with extracellular receptors.
What receptors do hydrophobic molecules interact with?
Hydrophobic molecules can pass through membranes so can interact with intracellular receptors.
What is a transmembrane receptor made up of and what does it do?
A cystine rich hydrophobic domain (head) which interacts with the ligand.
A hydrophobic tyrosine kinase domain (tail) that interacts with downstream signalling machinery.
How is information transmitted from the ligand receptor to the effector?
Dimerization.
Conformational changes to membrane receptors, which are associated with G proteins.
What is dimerization?
Each ligand binds to a receptor.
The receptor brings the ligands together and they activate each other.
What is a Drosophila eye made up of?
Each eye is made of 800 ommatidia.
What is in an ommatadia?
8 photoreceptors
4 cone cells
2 primary pigment cells
6 secondary pigment cells
3 tertiary pigment cells
What pathway is required for R (photoreceptor) cell recruitment?
Ras / Raf / MEK / ERK pathway.
What is Ras?
A small GTPase. Controlled by GEFs and GAPs.
What is a GEF?
G protein exchange factor.
What is a GAP?
GTPase activation protein.
What happens in the first stage of the Ras pathway?
PDGF ligand is dimerized.
It has a high affinity for receptors (K alpha)
What is the affinity for K alpha receptors?
10^-10 M
What happens in the second stage of the Ras pathway?
Trans membrane P-Y residues are phosphorylated in cytositic tail.
What happens in the third stage of the Ras pathway?
P-Y residues bind to SH2 domain on GRB2 adaptor protein.
