Part 3

Question 1

PI 3 Kinase/Akt pathway forms the initial steps in many signaling pathways. What are the steps that lead to AKT activation?

Answer 1

1) PI3K recruited to activation receptor tyrosine kinase via its SH2 domain
2) Converts PIP2 to PIP3
3) AKT is recruited to the PM by binding to PIP3
4) Phosphorylated by MTORC2 that binds to PIP3
5) AKT phosphorylates target proteins, TF, and other kinases
6) AKT regulates mTOR, KSK and bad signaling pathways

Question 2

What are the main steps leading to activation of transcription for TGF - beta/Smad pathway?

Answer 2

1) Type II receptor phosphorylates and activates type I
2) Type I phosphorylates Smad protein
3) Phosphorylated SMads form complexes and translocate to the nucleus to activate transcription

Question 3

What role does ubiquitination and proteasomes play in the activation of the NF-kB pathway?

Answer 3

Ubiquitination degrades an inhibitory subunit IKB allows NF-Kb pathway to work
Proteasomes carry out this ubiquitination
IKb is flagged by phosphorylation.