Ras Proto-oncogene Function

Question 1

Definition

Answer 1

Ras is a proto-oncogene, encoding an intracellular signaling protein

Question 2

What is the role of proto-oncogenes?

Answer 2

Aid in cell proliferation

Question 3

Activation process (three steps)

Answer 3

• growth factor binds to cell membrane receptors
• upon phosphorylation, the receptor becomes activated
  -> activation of the Ras protein (G protein) via GDP/GTP exchange

Question 4

Cascade effect

Answer 4

• Activated ras initiates a phosphorylation cascade involving protein kinases
• Cascade reaches the nucleus, activating a transcription factor

Question 5

Outcome

Answer 5

Transcription factor stimulates synthesis proteins regulating the cell cycle

Question 6

Normal function

Answer 6

Regulation of cell growth and division