Receptor Tyrosine Kinases (RTKs): Structure, Function, and Signaling Pathways

Question 1

Which of the following is NOT a defining characteristic of Receptor Tyrosine Kinases (RTKs)?

Accepted Answer

Dimerization is NOT required for RTK activation

Answer

Transmembrane proteins that extend into the extracellular space

Answer

Possess an intracellular kinase domain

Answer

Ligand-binding triggers receptor activation

Question 2

Which of the following is the first step in RTK-mediated signal transduction?

Accepted Answer

Ligand binding to the extracellular domain

Answer

Phosphorylation of tyrosine residues

Answer

Dimerization of the RTK

Answer

Activation of downstream signaling pathways

Question 3

What is the primary function of the SH2 domain in RTK signaling?

Accepted Answer

Binds specifically to phosphorylated tyrosine residues

Answer

Catalyzes the phosphorylation of tyrosine residues

Answer

Forms the ligand-binding site

Answer

Facilitates the dimerization of RTKs

Question 4

Which type of mutation in RTKs can lead to their constitutive activation?

Accepted Answer

Gain-of-function mutations in the ligand-binding domain

Answer

Loss-of-function mutations in the kinase domain

Answer

Deletions in the SH2 domain

Answer

Insertions in the transmembrane domain

Question 5

Which RTK is commonly associated with the development and progression of breast cancer?

Accepted Answer

HER2

Answer

EGFR

Answer

PDGFRA

Answer

VEGFR

Question 6

Which of the following is NOT a characteristic of Receptor Tyrosine Kinases (RTKs)?

Accepted Answer

Constitutively active kinase domain

Answer

Single-pass transmembrane proteins

Answer

Extracellular domain with glycosylation sites

Answer

Involvement in regulating cellular processes

Question 7

What is the primary mechanism by which RTKs initiate intracellular signal transduction?

Accepted Answer

Autophosphorylation of tyrosine residues

Answer

Phosphorylation by neighboring kinases

Answer

Binding to and activating G proteins

Answer

Activation of phospholipases

Question 8

What is the primary function of the extracellular ligand in RTK signaling?

Accepted Answer

Inducing conformational changes in the RTK

Answer

Stabilizing the formation of RTK dimers

Answer

Inhibiting RTK autophosphorylation

Answer

Activating the kinase domain of the RTK

Question 9

What is the role of tyrosine phosphorylation in RTK signaling?

Accepted Answer

Creates docking sites for downstream signaling molecules

Answer

Activates the kinase domain of the RTK

Answer

Stabilizes the RTK dimer

Answer

Inhibits RTK autophosphorylation

Question 10

What molecules directly trigger the activation of Receptor Tyrosine Kinases (RTKs)?

Accepted Answer

Ligands

Answer

G proteins

Answer

Phospholipids

Answer

Calcium ions

Question 11

What is the main function of RTKs in cell signaling?

Accepted Answer

To bind specific ligands and initiate intracellular signaling pathways.

Answer

To hydrolyze ATP and release phosphate groups.

Answer

To transport ions across the cell membrane.

Answer

To regulate gene expression directly.

Question 12

What is the role of adaptor proteins in RTK signaling?

Accepted Answer

To link RTKs to downstream signaling pathways.

Answer

To amplify the signal generated by RTKs.

Answer

To inhibit RTK activity.

Answer

To transport RTKs to the plasma membrane.

Question 13

How do RTKs contribute to cell proliferation?

Accepted Answer

By activating the MAPK pathway.

Answer

By suppressing the PI3K pathway.

Answer

By inhibiting the STAT pathway.

Answer

By directly phosphorylating cell cycle proteins.

Question 14

How do RTKs contribute to the development of targeted cancer therapies?

Accepted Answer

By providing specific molecular targets for drug development.

Answer

By facilitating the delivery of drugs to cancer cells.

Answer

By suppressing the immune system, enabling cancer cells to evade detection.

Answer

By promoting cell death and apoptosis.

Question 15

How does the activation of different Receptor Tyrosine Kinases (RTKs) lead to diverse cellular responses?

Accepted Answer

Each RTK binds to a specific ligand, triggering unique downstream signaling pathways that result in tailored cellular responses.

Answer

All RTKs activate the same downstream signaling pathway, regardless of the ligand they bind.

Answer

RTK activation solely depends on their dimerization status and is independent of ligand binding.

Answer

The cellular response triggered by RTKs is independent of the specific RTK activated.

Question 16

Which of the following best defines Receptor Tyrosine Kinases (RTKs)?

Accepted Answer

Cell surface receptors that possess an intrinsic tyrosine kinase activity and a transmembrane domain.

Answer

Cytoplasmic proteins that interact with G proteins.

Answer

Ligand-binding receptors that recognize only serine residues.

Question 17

What is the central role of RTKs in cellular signaling?

Accepted Answer

Initiating intracellular signaling cascades by phosphorylating tyrosine residues on target proteins.

Answer

Activating G proteins and regulating calcium release.

Answer

Transporting ligands across the plasma membrane.

Question 18

Which signaling pathway is predominantly activated downstream of RTKs?

Accepted Answer

MAPK pathway

Answer

Jak-STAT pathway

Answer

TGF-beta pathway

Answer

Wnt pathway

Question 19

What is a potential consequence of dysregulated RTK overactivation?

Accepted Answer

Cancer

Answer

Diabetes

Answer

Neurodegenerative diseases

Answer

Autoimmune disorders

Question 20

Which technique is commonly employed to study RTK activity?

Accepted Answer

Immunoprecipitation

Answer

Mass spectrometry

Answer

X-ray crystallography

Answer

Electrophoresis

Question 21

What is the primary function of the extracellular immunoglobulin-like domains in RTKs?

Accepted Answer

Ligand binding

Answer

Signal transduction

Answer

Membrane anchoring

Answer

Protein-protein interactions

Question 22

Which of the following is different from a Receptor Tyrosine Kinase?

Accepted Answer

Non-receptor tyrosine kinase

Answer

Insulin receptor

Answer

TAM receptor

Answer

HER2 receptor

Question 23

How does autophosphorylation contribute to RTK activation?

Accepted Answer

It creates binding sites for adapter proteins.

Answer

It releases the ligand from the receptor

Answer

It inhibits the kinase domain

Answer

It triggers GTPase activity