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What is the result of RTK activation on IRS docking protein?

  • It activates MAPK directly.
  • It inhibits PDK1 recruitment.
  • It recruits PI3K to the plasma membrane. (correct)
  • It increases PIP2 levels.

    • What is produced when PI3K phosphorylates PIP2?

  • DAG
  • IP3
  • PIP1
  • PIP3 (correct)

    • Which of the following pathways is NOT triggered by activated RTKs?

  • Ras → MAPK
  • NFKB → AP-1 (correct)
  • PIP3 → AKT
  • PLCγ → IP3/DAG

    • Which protein is directly phosphorylated by Akt on Thr308 and Ser473?

    <p>PKB</p> Signup and view all the answers

    What type of growth factors can act as ligands for RTKs?

    <p>Vascular Endothelial Growth Factor (VEGF)</p> Signup and view all the answers

    What hormone is released from the pancreas in response to low glucose levels?

    <p>Glucagon</p> Signup and view all the answers

    Which receptor type does glucagon activate for its effects in the liver?

    <p>Glucagon GPCR</p> Signup and view all the answers

    What is the primary action of insulin on glucose levels?

    <p>Stimulate glucose uptake</p> Signup and view all the answers

    What triggers the release of glucagon?

    <p>Low glucose levels</p> Signup and view all the answers

    What is the primary role of second messengers in cellular signaling?

    <p>They activate or inactivate target proteins.</p> Signup and view all the answers

    Which hormone is released from the adrenal gland during the fight or flight response?

    <p>Epinephrine</p> Signup and view all the answers

    Which receptor type is known for its role in immune responses and generating diversity?

    <p>Specialized receptors</p> Signup and view all the answers

    Which signaling pathway is associated with insulin action?

    <p>RTK signaling pathway</p> Signup and view all the answers

    In the context of glucagon, which process is stimulated in the liver?

    <p>Glycogenolysis</p> Signup and view all the answers

    What is a defining characteristic of receptor protein-tyrosine kinases (RTKs)?

    <p>They have tyrosine protein kinase activity within their intracellular domains.</p> Signup and view all the answers

    Which common ligand is associated with receptor protein-tyrosine kinases?

    <p>Insulin</p> Signup and view all the answers

    What is one of the signaling pathways triggered by insulin?

    <p>IP3/DAG pathway</p> Signup and view all the answers

    What effect does epinephrine have on glycogen in the liver?

    <p>Stimulates glycogen breakdown</p> Signup and view all the answers

    What occurs during the ligand-mediated dimerization of receptor protein-tyrosine kinases?

    <p>One ligand binds to two receptor proteins simultaneously.</p> Signup and view all the answers

    What is the role of insulin receptor substrate 1 (IRS1) in insulin signaling?

    <p>Initiates metabolic pathways</p> Signup and view all the answers

    HER2 is a type of which receptor that promotes the growth of cancer cells?

    <p>Receptor protein-tyrosine kinase</p> Signup and view all the answers

    What is the result of receptor-mediated dimerization in signaling pathways?

    <p>Association of two receptor proteins through ligands</p> Signup and view all the answers

    Which signaling pathway does vascular endothelial growth factor (VEGF) primarily activate?

    <p>Proliferation signaling pathway</p> Signup and view all the answers

    What physiological effect do receptor protein-tyrosine kinases notably influence?

    <p>Growth and cellular differentiation</p> Signup and view all the answers

    What is the process called when RTKs add phosphate groups to their own tyrosine residues?

    <p>Trans-autophosphorylation</p> Signup and view all the answers

    What role do inactive relay proteins play in RTK signaling?

    <p>They are phosphorylated and activated</p> Signup and view all the answers

    What can result from a cell's failure to stop responding to growth factor signals?

    <p>Uncontrolled mitosis leading to cancer</p> Signup and view all the answers

    What process is required to terminate signaling in RTKs?

    <p>Endocytosis</p> Signup and view all the answers

    What role does the CBL protein play in RTK signaling?

    <p>Ubiquitinating RTK for internalization</p> Signup and view all the answers

    Which type of relay protein functions as a linker in a signaling complex?

    <p>Adaptor proteins</p> Signup and view all the answers

    How do docking proteins function in RTK signaling?

    <p>They act as docking stations for signaling proteins</p> Signup and view all the answers

    What type of proteins translocate to the nucleus when activated by RTKs?

    <p>Transcription factors</p> Signup and view all the answers

    Which of the following is not a type of relay protein mentioned in RTK signaling?

    <p>Structural proteins</p> Signup and view all the answers

    What must happen to RTKs after they have transmitted a signal?

    <p>They undergo endocytosis or degradation</p> Signup and view all the answers

    Which type of receptor is characterized by its ability to transfer phosphate groups to tyrosine residues?

    <p>Receptor protein-tyrosine kinases (RTKs)</p> Signup and view all the answers

    Which second messenger is produced when the ligand binds to a G-protein coupled receptor and activates adenylyl cyclase?

    <p>cAMP</p> Signup and view all the answers

    What is the primary function of Protein Kinase A (PKA)?

    <p>To phosphorylate serine and threonine residues</p> Signup and view all the answers

    Which of the following ligands would activate phospholipase C-beta when binding to a G-protein coupled receptor?

    <p>Acetylcholine</p> Signup and view all the answers

    What is the effect of the G-protein alpha subunit Gs when activated?

    <p>Activates adenylyl cyclase activity</p> Signup and view all the answers

    Which pathway is initiated by GPCRs that leads to the production of cGMP?

    <p>Gt pathway</p> Signup and view all the answers

    The activation of which enzyme causes membrane hyperpolarization by closing cation channels?

    <p>Phosphodiesterase</p> Signup and view all the answers

    What is the primary function of second messengers in cellular signaling?

    <p>To activate or inactivate target proteins</p> Signup and view all the answers

    Which of the following is a characteristic of receptor protein-tyrosine kinases (RTKs)?

    <p>They have tyrosine protein kinase activity in their intracellular domain</p> Signup and view all the answers

    What is one of the first steps during ligand-mediated dimerization of RTKs?

    <p>Ligand binding to two receptor proteins simultaneously</p> Signup and view all the answers

    Which of these ligands is commonly associated with receptor protein-tyrosine kinases?

    <p>Insulin</p> Signup and view all the answers

    Which role do G-protein coupled receptors (GPCRs) play in cell signaling?

    <p>They recruit signaling proteins to their intracellular domains</p> Signup and view all the answers

    What is a potential consequence of the uncontrolled signaling from activated RTKs in cells?

    <p>Increased cell proliferation</p> Signup and view all the answers

    What process is initiated when a ligand binds to a receptor protein-tyrosine kinase (RTK)?

    <p>Dimerization of receptor proteins</p> Signup and view all the answers

    What is the result of RTK trans-autophosphorylation?

    <p>Phosphate groups are added to tyrosine residues</p> Signup and view all the answers

    What is the function of relay proteins in the context of RTK signaling?

    <p>To act as docking stations for signaling proteins</p> Signup and view all the answers

    Which mechanism is NOT involved in ending the response of RTKs?

    <p>Phosphorylation of cytoplasmic proteins</p> Signup and view all the answers

    Which type of relay protein can translocate to the nucleus upon activation?

    <p>Transcription factors</p> Signup and view all the answers

    What is required for a cell to effectively terminate signaling through RTKs?

    <p>Destruction or endocytosis of the RTK</p> Signup and view all the answers

    Which of the following best describes the role of CBL protein in RTK signaling?

    <p>It mediates the internalization of RTK complexes</p> Signup and view all the answers

    What is a characteristic of adaptor proteins in RTK signaling?

    <p>They serve as a link between signaling proteins</p> Signup and view all the answers

    What can lead to uncontrolled cell division or cancer in relation to RTKs?

    <p>Failure to halt signaling appropriately</p> Signup and view all the answers

    Which type of relay protein functions as a docking station for multiple signaling proteins?

    <p>Docking proteins</p> Signup and view all the answers

    What is the role of PI3K within the signaling pathway involving receptor protein-tyrosine kinases (RTKs)?

    <p>To phosphorylate lipids in the plasma membrane</p> Signup and view all the answers

    Which phosphorylation events are key in the activation of Akt in the signaling pathway?

    <p>Phosphorylation on Thr308 and Ser473</p> Signup and view all the answers

    What is one of the major signaling pathways triggered by the activation of receptor protein-tyrosine kinases (RTKs)?

    <p>Ras → MAPK</p> Signup and view all the answers

    During the activation of receptor protein-tyrosine kinases (RTKs), what is the initial event that leads to downstream signaling?

    <p>Phosphorylation of the receptor's tyrosine residues</p> Signup and view all the answers

    Which of these ligands is commonly known to activate receptor protein-tyrosine kinases (RTKs)?

    <p>Vascular Endothelial Growth Factor (VEGF)</p> Signup and view all the answers

    What effect does glucagon have in the liver?

    <p>Promotes glycogen breakdown</p> Signup and view all the answers

    Which receptor type is activated by epinephrine in response to stress?

    <p>Beta-adrenergic receptor</p> Signup and view all the answers

    Insulin primarily promotes which of the following processes?

    <p>Glucose uptake</p> Signup and view all the answers

    What is the primary action of phospholipase C-γ (PLC-γ) when activated by receptor protein-tyrosine kinases (RTKs)?

    <p>To cleave PIP2 into IP3 and DAG</p> Signup and view all the answers

    Which major signaling pathway is NOT triggered by insulin?

    <p>cAMP production</p> Signup and view all the answers

    What physiological change occurs when glucagon is released from the pancreas?

    <p>Increased hepatic glucose production</p> Signup and view all the answers

    Which pathway is initiated by the activation of the Ras protein in RTK signaling?

    <p>MAPK signaling pathway</p> Signup and view all the answers

    Which of the following is a common action of cAMP in cellular signaling?

    <p>Activation of Protein Kinase A (PKA)</p> Signup and view all the answers

    Which of the following statements about PIP3 and IP3 is true?

    <p>PIP3 is formed by the phosphorylation of PIP2</p> Signup and view all the answers

    Which broad category does Protein Kinase C (PKC) activation fall under in RTK signaling?

    <p>Second messenger activation</p> Signup and view all the answers

    How does insulin exhibit its effects within cells?

    <p>Through receptor protein-tyrosine kinases</p> Signup and view all the answers

    What triggers the release of insulin from the pancreas?

    <p>High glucose levels</p> Signup and view all the answers

    Which of the following ligands is specifically associated with triggering RTK signaling?

    <p>Epidermal growth factor (EGF)</p> Signup and view all the answers

    Which second messenger is involved in the signaling pathway of insulin via RTKs?

    <p>PIP3</p> Signup and view all the answers

    What distinguishes GPCR signaling from RTK signaling in the context of IP3 and DAG production?

    <p>RTKs undergo autophosphorylation prior to PLC activation</p> Signup and view all the answers

    What is a primary function of receptor protein-tyrosine kinases (RTKs)?

    <p>To phosphorylate tyrosine residues</p> Signup and view all the answers

    How does phospholipase C-α (PLC-α) differ from phospholipase C-β (PLC-β) in G-protein coupled receptor signaling?

    <p>PLC-β is only activated by the beta-gamma subunit of G-proteins</p> Signup and view all the answers

    What is the role of the SH2 domain in phospholipase C-γ (PLC-γ) in RTK signaling?

    <p>It binds activated RTKs to initiate signaling</p> Signup and view all the answers

    Which component is released by both GPCRs and RTKs for intracellular signaling?

    <p>Inositol trisphosphate (IP3)</p> Signup and view all the answers

    What is the relationship between receptor protein-tyrosine kinases (RTKs) and growth factors?

    <p>Growth factors bind to RTKs to stimulate signaling pathways</p> Signup and view all the answers

    Which of the following statements accurately describes the role of G-protein coupled receptors (GPCRs)?

    <p>They activate specific G-proteins upon ligand binding.</p> Signup and view all the answers

    What is the primary role of cyclic AMP (cAMP) in cellular signaling?

    <p>To act as a second messenger that activates Protein Kinase A (PKA).</p> Signup and view all the answers

    What is a common mechanism that occurs after receptor protein-tyrosine kinases (RTKs) are activated?

    <p>They undergo dimerization and trans-autophosphorylation.</p> Signup and view all the answers

    Which of the following is NOT a consequence of GPCR activation?

    <p>Decreased production of inositol trisphosphate (IP3).</p> Signup and view all the answers

    What initiates the signaling process of receptor protein-tyrosine kinases (RTKs)?

    <p>Conformational change in the receptor due to ligand binding.</p> Signup and view all the answers

    Which of the following best explains the specific action of epinephrine in cellular pathways?

    <p>It binds to GPCRs, influencing various pathways including cAMP production.</p> Signup and view all the answers

    Which type of signaling is primarily facilitated by specialized receptors, such as B-and T-cell receptors?

    <p>Immune response signaling leading to diversity.</p> Signup and view all the answers

    Which component is directly responsible for the phosphorylation of MEK in the RAS-MAPK signaling cascade?

    <p>Raf protein</p> Signup and view all the answers

    What is the primary function of ERK in the MAPK signaling pathway?

    <p>It regulates gene expression</p> Signup and view all the answers

    Which of the following correctly describes MAPKKK in the signaling cascade?

    <p>It initiates the cascade by phosphorylating other kinases.</p> Signup and view all the answers

    In the context of the RAS-MAPK pathway, what role does GDP play?

    <p>It is exchanged for GTP during Ras activation.</p> Signup and view all the answers

    Which of the following statements about the MAPK pathways is true?

    <p>Different extracellular signals can activate different combinations of MAPK pathways.</p> Signup and view all the answers

    What is the primary role of receptor protein-tyrosine kinases (RTKs) in cell signaling?

    <p>They mediate dimerization upon ligand binding.</p> Signup and view all the answers

    Which statement accurately describes a feature of G-protein coupled receptors (GPCRs)?

    <p>They can initiate signaling cascades by activating intracellular second messengers.</p> Signup and view all the answers

    What type of ligand binding leads to receptor dimerization in receptor protein-tyrosine kinases?

    <p>Single ligand binding to two receptors simultaneously.</p> Signup and view all the answers

    Which of the following ligands is least likely to interact with receptor protein-tyrosine kinases?

    <p>Norepinephrine</p> Signup and view all the answers

    What is a significant effect of the HER2 receptor's activation in breast cancer?

    <p>Inhibition of apoptosis in cancer cells.</p> Signup and view all the answers

    What common pathway is initiated by receptor protein-tyrosine kinases upon ligand binding?

    <p>Transcriptional activation in the nucleus through relay proteins.</p> Signup and view all the answers

    Which component is crucial for the transactivation of receptor protein-tyrosine kinases?

    <p>Ligand-induced conformational change.</p> Signup and view all the answers

    What is a consequence of the activation of tyrosine kinase activity in RTKs?

    <p>Phosphorylation of tyrosine residues on target proteins.</p> Signup and view all the answers

    Which type of receptor is specifically implicated in generating diversity in immune responses?

    <p>Specialized B- and T-cell receptors.</p> Signup and view all the answers

    Which of the following best describes a characteristic of phospholipase C-γ (PLC-γ) when activated by RTKs?

    <p>It cleaves PIP2 to generate IP3 and DAG.</p> Signup and view all the answers

    Which pathway is initiated by activated RTKs that leads to cellular responses?

    <p>Ras → MAPK</p> Signup and view all the answers

    What is the primary role of inositol trisphosphate (IP3) after its production by PLC-γ?

    <p>Triggers the release of Ca2+ from intracellular stores.</p> Signup and view all the answers

    How does the activation of PLC-β by GPCRs differ from the activation of PLC-γ by RTKs?

    <p>PLC-β is activated by G-protein interaction, while PLC-γ is activated by RTK autophosphorylation.</p> Signup and view all the answers

    What distinguishes PIP3 from IP3 in terms of their formation?

    <p>PIP3 is produced when PIP2 is phosphorylated without cleavage.</p> Signup and view all the answers

    Which second messenger pathway is shared by both GPCRs and RTKs?

    <p>Mobilization of calcium ions</p> Signup and view all the answers

    What effect does DAG have in the cell after being produced by PLC-γ?

    <p>It acts as a co-activator for Protein Kinase C (PKC).</p> Signup and view all the answers

    Which of the following ligands is NOT typically associated with receptor protein-tyrosine kinases?

    <p>G-protein coupled receptor ligands</p> Signup and view all the answers

    Which statement best encapsulates the relationship between RTKs and their downstream effects?

    <p>RTKs can activate multiple signaling pathways leading to diverse cellular responses.</p> Signup and view all the answers

    What is the primary consequence of excessive signaling through receptor protein-tyrosine kinases?

    <p>Uncontrolled cell growth and cancer development.</p> Signup and view all the answers

    What effect does glucagon have on liver glycogen?

    <p>Stimulates breakdown of glycogen</p> Signup and view all the answers

    Which signaling pathway is primarily triggered by insulin?

    <p>PI3K pathway</p> Signup and view all the answers

    What is the primary action of epinephrine in the liver?

    <p>Stimulating glycogen breakdown and glucose release</p> Signup and view all the answers

    Which hormone enhances glucose uptake and storage in the liver?

    <p>Insulin</p> Signup and view all the answers

    What role does IRS1 play in insulin signaling?

    <p>Mediates signaling through various pathways</p> Signup and view all the answers

    What type of receptor does glucagon bind to in the liver?

    <p>G-protein coupled receptor (GPCR)</p> Signup and view all the answers

    Which of the following is NOT a pathway triggered by insulin signaling?

    <p>cAMP pathway</p> Signup and view all the answers

    What triggers the release of insulin?

    <p>High glucose levels</p> Signup and view all the answers

    Which component is involved in the second messenger system associated with insulin signaling?

    <p>PIP3</p> Signup and view all the answers

    During the fight or flight response, which hormone is primarily released to mobilize energy?

    <p>Epinephrine</p> Signup and view all the answers

    Study Notes

    HSS2305: Molecular Mechanisms of Disease

    • Molecular Mechanisms of Disease is the subject of the lecture, and the lecture is labelled as Lecture 17.
    • Signal Transduction: RTKs and MAPKs is the specific topic covered.
    • Prof. Keir Menzies delivered the lecture.
    • Final Exam: Scheduled for Thursday, 12/12/2024, from 9:30 AM to 12:30 PM. The test location is 100 Louis Pasteur (CRX) C442.
    • Exam Content: Studying from lecture 8 through gene transcription and translation is part of the 45% of the final mark. This segment is not cumulative. The final will be in-person. Respondus Lockdown Browser or Zoom proctoring will be used for the final exam.
    • Cell Signaling Receptors: Receptor types include G-protein coupled receptors (GPCRs), Receptor protein-tyrosine kinases (RTKs), ligand-gated channels, steroid hormone receptors, and specialized receptors. Specialized receptors include B-cell and T-cell receptors, responsible for immune diversity.
    • Ligand-gated channels: Allow or conduct passage of ions.
    • Steroid hormone receptors and nuclear receptors: are also receptor types.
    • Signal Transduction Pathways: There are multiple types of intracellular second messenger pathways initiated by receptors. The text highlights pathways involving cAMP (e.g., glucagon, epinephrine), GMP (e.g., light/rhodopsin), and IP3/DAG (e.g., epinephrine, acetylcholine, serotonin).
    • Cell Signaling: The cell signaling process has two major transmission routes: (1) Generation of second messengers via effector enzymes and (2) recruitment of signalling proteins to intracelluar domains initiating a protein-activated cascade.
    • Cell Signaling and Receptors: Important types and examples of receptor proteins, including types like G-protein coupled receptors (GPCRs), RTKs (receptor tyrosine kinases), ligand-gated channels, and steroid receptors (nuclear receptors). These factors regulate a wide range of cellular functions and responses.
    • Receptor Protein Tyrosine Kinases (RTKs) are also detailed with ligand binding sites and activated relay proteins.
    • RTK Pathways: The text discusses multiple detailed pathways including autophosphorylation mechanisms, recruitment of specific relay proteins (like SH2-containing proteins), trans-autophosphorylation actions of the RTK, and how these relay proteins help with different cellular responses.
    • Common Ligands: Insulin, VEGF, PDGF, EGF, and FGF are discussed as examples.
    • General Cell Signaling: The concept of "cross-talk" is emphasized. This refers to signals passing forward or backward between different pathways which influence and modulate each other.
    • Signaling Pathways and Receptors: The text emphasizes how receptors and different signalling pathways impact cellular responses, including but not limited to growth, cell proliferation, gene expression, etc.
    • Examples of Ligands: VEGF, PDGF, and EGF.
    • Regulation of Blood Glucose: The lecture emphasizes hormonal regulation of blood glucose. Glucagon and epinephrine are described as examples of hormones regulating glucose mobilization.
    • Insulin Signaling: This hormone's role in regulating blood glucose levels is addressed.
    • PIP3 → AKT Pathway: Important molecules like IRS, PI3K recruitment, PDK1, PDK2, Akt. Ligands are also noted.
    • Ras → MAPK Pathway: Key steps in the Ras pathway, including the role of the Ras protein, autophosphorylation of the receptor, recruitment of adapter proteins (Grb2, Sos), stimulation of Ras, phosphorylation activity.
    • Other Signalling Pathway Types: The lecture details various signaling pathways such as PLCγ → IP3/DAG, PIP3 → AKT, and Ras → MAPK.
    • MAPK cascades: These pathways are complex and involve multiple steps to regulate different cellular responses in mammals. ERK, p38, and JNK pathways are highlighted.
    • Convergence and Divergence: The text points out how different signals converge to a pathway; the same signal can have various impacts.
    • Next Lecture: A future lecture is announced, with no further content related to the next one explained.

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    Description

    This quiz focuses on Lecture 17 of HSS2305: Molecular Mechanisms of Disease, delivered by Prof. Keir Menzies. It covers the critical topic of Signal Transduction, specifically relating to RTKs and MAPKs, and prepares you for the final exam. Enhance your understanding of various cell signaling receptors and their roles in molecular pathways.

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