Ras and Cancer

Question 1

__________
- Any activator in the pathway
- Growth factor protein ligand,
receptor kinase, Ras, MAP kinases, transcription factors
- Anything that increases the gene expression leading to cell division would increase cell division

Answer 1

Molecules in the Receptor Kinase pathway that are encoded by proto-oncogenes

Question 2

_________
Phosphatases and other proteins that function in signal
termination (since these would decrease the gene expression for cell division)

Answer 2

Molecules in the Receptor Kinase pathway that are encoded by tumor suppressor genes

Question 3

Mutations typically associated with cancer
Mutations to proto-oncogenes that …

Answer 3

Make these proteins over-active and unregulated

Question 4

Mutations typically associated with cancer
Mutations to tumor suppressor genes that …

Answer 4

Makes these proteins nonfunctional or decrease their function

Question 5

Why is new gene expression of cyclins required for a cell to enter the cell cycle?

Answer 5

All cyclins are degraded in M phase

Question 6

What percent of cancers show mutations to Ras?

Answer 6

30% (but 2% have the specific Ras mutation that the drug targets)

Question 7

Why was Ras previously regarded by researchers as ‘undruggable’?

Answer 7

Because the GTP that binds to and activates Ras binds very tightly

Question 8

Ras is active because it is bound to proteins called ______, which causes Ras to exchange the small molecule ______ for ______.

Answer 8

Adaptors, GDP, GTP

Question 9

Active Ras activates the protein ______ using the signal transduction mechanism of ______ to _____ interactions.

Answer 9

Raf, protein, protein

Question 10

Where do the phosphates come from?

Answer 10

ATP

Question 11

Which enzyme transfers a phosphate to Mek?

Answer 11

Raf (a MAP Kinase Kinase Kinase)

Question 12

Which enzymes in the pathway function as kinases? (Multiple)
Ras / Raf / Mek / Erk / Transcription Factors

Answer 12

Raf, Mek, Erk