Biosignaling - Receptor Tyrosine Kinases & Insulin

The video explains the receptor tyrosine kinase (RTK) pathway, focusing on insulin signaling. It describes how insulin binds to RTK, causing dimerization and activation through auto-phosphorylation. The pathway involves a series of proteins, including IRS-1, GRB2, SOS, and RAF1, leading to gene transcription. The video also discusses the role of RTKs in growth factor signaling and the potential for mutations in this pathway to cause cancer.

What is the primary function of receptor tyrosine kinases (RTKs) when activated by insulin?

• To phosphorylate tyrosine residues on themselves and other proteins

• To inhibit cellular growth and division

• To break down insulin into smaller molecules

• To transport glucose directly into cells

What happens to the insulin receptor when insulin binds to it?

• It dimerizes and becomes activated

• It dissociates into monomers

• It forms a heterodimer with another receptor

• It is internalized into the cell

Which protein is directly phosphorylated by the activated insulin receptor to initiate the signaling cascade?

• GRB2

• SOS

• RAF-1

• IRS-1

What is the role of RAF-1 in the insulin signaling pathway?

• It acts as a transcription factor

• It deactivates the insulin receptor

• It binds to insulin directly

• It phosphorylates and activates MEK

Which protein enters the nucleus to influence gene transcription in the insulin signaling pathway?

• RAF-1

• ERK

• MEK

• IRS-1

What is the primary role of ERK in the insulin signaling pathway?

• To phosphorylate IRS-1

• To activate transcription factors in the nucleus

• To bind directly to insulin

• To inhibit MEK

What is a common characteristic of molecules that bind to RTKs?

• They are usually neurotransmitters

• They are typically small ions

• They are often growth factors

• They are always hormones

How can mutations in the Ras protein lead to cancer?

• By causing continuous activation of the signaling pathway

• By preventing insulin binding

• By increasing the degradation of growth factors

• By inhibiting cell division

What is the consequence of a mutation that slows down the GTPase activity of Ras?

• Ras is unable to bind GTP

• Ras remains active for longer periods

• Ras is degraded more quickly

• Ras becomes inactive

Which of the following is NOT a potential outcome of RTK pathway dysregulation?

• Uncontrolled cell growth

• Cancer development

• Increased insulin sensitivity

• Altered gene transcription