Ras Raf MEK ERK Signalling Pathway (youtube)

Question 1

What type of pathway is the Ras-Raf-MEK-ERK pathway?

Answer 1

A mitogen-activated protein kinase (MAPK) cascade

Question 2

What is Ras?

Answer 2

A small guanosine triphosphatases (GTPase) with 3 forms (H-ras, K-ras, N-ras)

Question 3

What is MEK?

Answer 3

MAPK/ERK Kinase

Question 4

What is ERK?

Answer 4

Extracellular receptor kinase

Question 5

What does ERK do?

Answer 5

Regulates various cytosolic and nuclear proteins (>160 proteins, including transcription factors, survival, meta sis proteins)

Question 6

What is the basic Ras-Raf-MEK-ERK pathway?

Answer 6

Ras activates (B-)raf
Which activates MEK1/2
Which activates ERK1/2

Question 7

What happens once ERK is activated?

Answer 7

It is translocated to the nucleus where it will activate several genes and transcription factors

Question 8

What are some examples of genes/transcription factors that ERK activates?

Answer 8

Ets, c-Myc, c-Jun, c-Fos

They are related to cell proliferation, survival, and metastasis

Question 9

What is Ras regulated by?

Answer 9

EGFR (epidermal growth factor receptor) or Her2

Question 10

How is Ras regulated?

Answer 10

EGFR activates Sos and Grb2 protein which then activates Ras

Question 11

How is EGFR activated?

Answer 11

By TGFa (transforming growth factor alpha)
Or EGF, betacellulin, epiregulin

Question 12

How is the ras-raf-ERK-MEK able to essentially activate itself?

Answer 12

EGFR is activated by TGFa

TGFa is able to be translated once ERK1/2 activates its gene

Question 13

How is Raf regulated?

Answer 13

By PAK (p20 activated kinase)
Or Src, or binding partners