The Four Different Pathways Flashcards
With over twenty types, this is the largest family of enzyme receptors
tyrosine kinase receptors
What pathway is linked to survival, growth, proliferation, and metabolism
Tyr-K
What must occur for activation of Tyr-K
Dimerisation and autophospsorylation
How does Tyr-K signal?
Via SH2 domain
What are the main secondary messengers of Tyr-K?
Ras and phospholipase
What are some ligands that are used for Tyr-K (2)
Insulin and growth factors (NGF)
Name, from left to right, the parts that make up the tyrosine kinase connecting the Ras
Ras, Sos, GRB2, and phosphorylated tyrosine kinase
What happens when tyrosine kinase passes it signal to Ras?
the Ras drops the GDP it was holding, picks up a GTP, and then drops of into the cell
name the growth factor that stimulates a cascade that promotes survival and differentiation
NGF growth factor
What are two important products of the NGF cascade?
BCL2 and AKT (phosporylates Bad so it wont work)
What is the secondary messenger that initiates the cascade for both BCL2 and phosphorylated Bad?
PI3K
What is MAPKs job?
ensures that BCL2 stays active, and it can also signal dna transcription
What does BCL2 do anyway?
inhibits ligand gated ion channels from opening in the mitochondria to release calcium
What is the role of PI3K?
Keeps Bad phosphorylated
PLC (Phospholipase C)is used for what?
It can cleave PIP2 into Dag and IP3
What can PIP2 do?
it can cleave into phospholipids into Dag and turns into InsP3
What can IP3 do?
It can open the ligand gated ion channel ON THE ER!!!
What is there an absence of in GPCRs?
enzymes. no enzymes are used in this process
How do GPCRs relay the message?
The have an alpha subunit that activates an amplifier enzyme some distance away
What does GPCR stand for
G-Protein Coupled Receptors
what are the two main GPCR pathways?
cAMP and PIP
What does cAMP determine?
PKA activity
After the GCPR receptor, what happens to the Alpha subunit?
It drops the GDP, binds GTP, and detaches and goes to activate an amplifier enzyme.
In the camp pathway, what does the alpha subunit activate?
It activates adenylate cyclase
What is the role of adenylate cyclase
Catalyzes the conversion of ATP into cAMP
What does camp do?
It can activate PKA by binding to and releasing the regulatory subunit
How many times do GPCRs cross the membrane?
7 times
What two signallers are from the same family?
Ras from Tyr-K and a-subunit from GPCRs
What is the role of PKA?
It phosphorylates proteins, channels, etc.
In the PIP/IP3 pathway, what does the alpha subunit activate?
Phospholipase C
What is the role of Phospholipase C?
It cleaves IP2 into IP3 and DAG
What can DAG do?
It can activate PKC with the help of calcium
what does arachodonic acid lead to?
eicosanoids
Can calcium govern PKC by itself?
yes
What is the difference between cyclic amp and gmp structurally?
The NH2 group is on the top of the nitrogenous base
What does a DAG look like?
A phospholipid with the head chopped off
What does inositol trisphosphate look like?
Just a ring with phosphates off of it
What makes GRB2 a good adapter?
It has has SH2 and SH3 domains
What is the end goal of the NGF cascade?
To activate MAPK, which keeps BCL2 active
