Biosignaling - Receptor Tyrosine Kinases & Insulin

The video explains the receptor tyrosine kinase (RTK) and its role in insulin signaling. It details the mechanism of RTK activation through dimerization and auto phosphorylation, leading to a cascade of protein activations. This cascade includes IRS1, GRB2, SOS, and RAF1, ultimately resulting in gene transcription and regulation. The video also discusses how mutations in the RTK pathway can lead to cancer, highlighting the role of Ras protein in this process.

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

• To transport glucose directly into cells

• To phosphorylate tyrosine residues on themselves and other proteins

• To inhibit cellular growth and division

• To break down insulin into smaller molecules

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

• It dimerizes and becomes activated

• It forms a heterodimer with another receptor

• It dissociates into monomers

• It is internalized into the cell

What is the significance of the dimerization of RTKs?

• It prevents the receptor from being degraded

• It is necessary for the receptor's activation

• It allows the receptor to bind to glucose

• It causes the receptor to change shape

Which protein is directly phosphorylated by the activated insulin receptor?

• GRB2

• IRS-1

• SOS

• RAF-1

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

• It acts as a transcription factor

• It phosphorylates and activates MEK

• It binds to insulin directly

• It deactivates the insulin receptor

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

• SOS

• IRS-1

• ERK

• GRB2

What is the role of ERK once it is activated in the RTK pathway?

• It deactivates IRS-1

• It binds to insulin receptors

• It phosphorylates transcription factors in the nucleus

• It transports glucose into cells

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

• They are always hormones

• They are enzymes

• They are structural proteins

• They are typically growth factors

What potential outcome can result from mutations in the RTK signaling pathway?

• Increased insulin sensitivity

• Uncontrolled cell growth leading to cancer

• Decreased glucose uptake

• Enhanced immune response

Which protein in the RTK pathway is known for its slow GTPase activity, potentially leading to cancer?

• MEK

• RAS

• ERK

• RAF-1