Exam (elaborations)
L03 - Cell Signalling and Cancer Test Questions & 100% Correct Answers Latest UpdatE
- Course
- Institution
L03 - Cell Signalling and Cancer Test Questions & 100% Correct Answers Latest Updat
[Show more]
Seller
Follow
Content preview
L03 - Cell Signalling and Cancer Test Questions& 100% Correct Answers Latest Update
Describe the process of receptor tyrosine kinase dimerisation and activation... - ✔✔-binding of
the signalling molecule induces receptor dimerisation (activates internal tyrosine kinase domain_
-this enables kinase domains of neighbouring receptors to cross-phosphorylate each other on
multiple tyrosine residues (autophosphorylation)
-phosphorylation of tyrosine residues creates high affinity docking sites for a variety of proteins (for
down stream signalling): >Grb-2 (MAP kinase pathway) >PI 3-kinase (PI 3-kinase pathway)
What does RAS activation act as? - ✔✔as a switch - key intermediate in the MAP kinase pathway
What type of gene is the activation of RAS? - ✔✔oncogene - activating RAS mutations are found
in around 30% of human tumours
What is RAS a master regulator of? - ✔✔many signalling pathways - does a lot of things in a cell which
makes targeting for cancer a lot harder
How is RAS - G-protein activates and inactivated - ✔✔RAS-GTP in the active form - GEF
(guanine nucleotide exchange factor ) stimulates the exchange of GDP for GTP
RAS-GDP is the inactive form - GAP (GTPase activating protein - yet it does deactivate) stimulates
intrinsic GTPase activity and hydrolysis of GTP
, Describe the MAPK pathway... - ✔✔-RAS binds to RAF family members and promotes RAF-
dimerisation and activation in a complex multi-faceted process involving phosphorylation (indirect
as RAS isn't putting the phosphate of RAF)
-activation of RAF kinase leads to rapid signalling through the MAPK cascade (RAF -> MEK -> ERK) via a
series of activating phosphorylation events
-phospho-ERK translocates to the nucleus and activates transcription factors such as FOS and JUN by
phosphorylation - this leads to changes in gene expression profiles
What does PI3K pathway stand for? - ✔✔phosphatidylinositol 3 kinase pathway
Describe the PI3K pathway... - ✔✔-the enzyme PI 3-kinase is activated by binding to
phosphorylated Tyr residues on RTKs
-PI 3-kinase catalyses the phosphorylation of PI(4,5)P2 to generate PI(3,4,5)P3
-PI(3,4,5)P3 acts as a docking site for 2 proteins, PDK1 and AKT
-upon binding PDK1 phosphorylates and activates AKT
-active AKT is released into the cytosol for downstream signalling (can activate mTOR, cause gene
transcription and cell cycle progression or phosphorylate and sequester pro-apoptotic proteins)
Describe the process from PI yo PI(3,4,5)P3... - ✔✔-PI - the inositol head group gets phosphorylated
-this forms PI(4,5)P2 (a substrate for PI3 kinase
-P1(4,5)P2 is phosphorylated by PI3K to produce PI(3,4,5)P3
What is PI(3,4,5)P3? - ✔✔a second messenger
What is a second messenger? - ✔✔a small molecule that passes signal on within the cell
How is EGFR family signalling switched off? - ✔✔1. remove extracellular signal so no stimulation
2. switching off activated receptor tyrosine kinase by protein tyrosine phosphatases (PTPs) -
remove phosphate group internally
3. dephosphorylation of target proteins by serine/threonine phosphatases
4. PTEN (phosphatase and tennis homolog deleted on chromosome 10) removal of PI(3,4,5)P3 signal
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller KenAli. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79373 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now