Cell Signaling & G Protein-coupled Receptors Quiz
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Questions and Answers

What is the function of the transmembrane domain of membrane receptors?

  • It binds the first messenger
  • It responds to the first messenger by changing conformation
  • It allows transducer function
  • It connects the two components (correct)

    • How do agonists affect the receptor?

  • They bind specifically to the receptor
  • They cause a conformational change in the receptor (correct)
  • They inhibit the function of antagonists
  • They do not lead to an intracellular signal

    • What determines binding specificity and affinity between ligands and receptors?

  • The type of transducer activated
  • The number of domains in the receptor
  • The location of the receptor
  • The extent of molecular complementarity (correct)

    • What does a given ligand binding to different types of receptors activate?

    <p>Different cell responses</p> Signup and view all the answers

    What is the role of the intracellular domain of membrane receptors?

    <p>It allows transducer function</p> Signup and view all the answers

    How do antagonists affect the receptor?

    <p>They do not lead to an intracellular signal</p> Signup and view all the answers

    In what way may two receptors that bind different ligands signal within a single cell?

    <p>Using different types of transducers/ effectors</p> Signup and view all the answers

    What activates different cell responses with a given ligand binding to different types of receptors?

    <p>The type of transducer activated</p> Signup and view all the answers

    What are the extracellular signaling molecules called?

    <p>First messengers</p> Signup and view all the answers

    Which organelles are involved in GPCR signaling according to the text?

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

    What is the main role of G protein-coupled receptors (GPCRs) in cell signaling?

    <p>Initiating intracellular signal transduction</p> Signup and view all the answers

    What is the effect of GPCR and transducer/effector localization mentioned in the text?

    <p>Biased signaling</p> Signup and view all the answers

    Which physiological responses are controlled by activation of signaling pathways as per the text?

    <p>Regulation of cardiac output and blood pressure</p> Signup and view all the answers

    What does insulin primarily regulate based on the information provided in the text?

    <p>Glucose uptake by muscle and liver cells</p> Signup and view all the answers

    Which location do membrane-bound receptors primarily occupy according to the text?

    <p>Cell surface</p> Signup and view all the answers

    Why are signaling pathways targeted by drugs according to the text?

    <p>To treat diseases</p> Signup and view all the answers

    Which proteins promote GTP hydrolysis by the α-subunit of heterotrimeric G proteins?

    <p>RGS domain-containing proteins</p> Signup and view all the answers

    How many types of alpha Gα subunits are there?

    <p>18</p> Signup and view all the answers

    Which type of G protein is designated by the alpha chain αs?

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

    What is the effector for the alpha subunit designated as Gs?

    <p>Adenylate cyclase</p> Signup and view all the answers

    How many types of beta Gg subunits are there?

    <p>5</p> Signup and view all the answers

    What can different combinations of G protein subunits form?

    <p>Several hundred potential combinations</p> Signup and view all the answers

    What do HA-TAG proteins form with respect to G protein subunits?

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

    What type of proteins are RGS domain-containing proteins?

    <p><em>Multi-functional</em>, GTPase-accelerating proteins</p> Signup and view all the answers

    How many regulators of G-protein signaling (RGS) domain-containing proteins have been identified in humans?

    <p>37</p> Signup and view all the answers

    What is the function of Gi with respect to adenylate cyclase?

    <p>Inhibits adenylate cyclase</p> Signup and view all the answers

    What is the main difference between the topology of class A and class B receptors?

    <p>The N-terminal region of class B receptors has a different crystallization technique applied compared to class A receptors.</p> Signup and view all the answers

    What marked the beginning of model peptides binding to GPCRs according to the text?

    <p>The binding of bovine rhodopsin (bRho) to GPCRs following a two-domain structure.</p> Signup and view all the answers

    What was used as the basis for the construction of the receptor molecular model?

    <p>The peptide binding to the first 7TM bundle to activate the structures more than 40 crystal structures.</p> Signup and view all the answers

    Which study served as the basis for electron cryomicroscopy, contributing to the understanding of GPCR structure?

    <p>bRho binding to GPCRs in 1983</p> Signup and view all the answers

    How many distinct GPCRs and ligand-receptor interactions were studied in the pioneering study mentioned in the text?

    <p>~44</p> Signup and view all the answers

    What was solved by Hollens et al. in 2013 and Wu et al. in 2014 in relation to GPCR structural biology?

    <p>Crystal structure of the extracellular domain (ECD) of GPCRs.</p> Signup and view all the answers

    What was noted as serving as a basis for the construction of receptor molecular models according to the text?

    <p>Peptide binding to the first 7TM bundle.</p> Signup and view all the answers

    What was bound to an inhibitor, as per the information provided in the text?

    <p>~44 distinct GPCRs.</p> Signup and view all the answers

    What was the year when the 3D structure of bRho in its inactive state was first revealed?

    <p>2000</p> Signup and view all the answers

    Which family of GPCRs comprises fifteen receptors in humans and is activated by small molecules such as amino acids?

    <p>Class C GPCRs</p> Signup and view all the answers

    Which part of the GPCR is called the 'venus flytrap domain' and contains the entire ligand binding site?

    <p>VFT domain</p> Signup and view all the answers

    Which type of GPCR family includes receptors for neurotransmitters and is classified into rhodopsin and nonrhodopsin receptors?

    <p>Glutamate family</p> Signup and view all the answers

    Which class of GPCR-ligand complexes presents diverse ligand-binding sites for small molecules such as amino acids?

    <p>Class A</p> Signup and view all the answers

    Which representative structure from Class B GPCR-ligand complexes is bound to negative allosteric modulators?

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

    What is the PDB ID associated with the representative structure from Class B GPCR-ligand complexes, CRF1?

    <p>4K5Y</p> Signup and view all the answers

    What marked the beginning of GPCR structural biology?

    <p>The pioneering study of the 2D structure for bovine rhodopsin (bRho)</p> Signup and view all the answers

    In what form do classic C receptors exist?

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

    What changes the orientation of transmembrane domains 3, 4, 5, 6, and 7?

    <p>Binding of agonists</p> Signup and view all the answers

    What served as the basis for the construction of the receptor molecular model in GPCR structural biology?

    <p>Calculation of a 2D projection map from solved 2D crystals of bRho</p> Signup and view all the answers

    What remained challenging despite relentless efforts in GPCR structural biology?

    <p>Elucidation of GPCR structures</p> Signup and view all the answers

    What was released in 2000, a decade after the pioneering study of the 2D structure for bovine rhodopsin?

    <p>The first three-dimensional (3D) structure of bRho in its inactive state</p> Signup and view all the answers

    What was calculated from the solved 2D crystals of bRho using electron cryomicroscopy?

    <p>A 2D projection map</p> Signup and view all the answers

    What enhances the interaction of ECDs and changes the orientation of transmembrane domains?

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

    Study Notes

    Membrane Receptors

    • The transmembrane domain of membrane receptors is responsible for anchoring the receptor in the membrane and transmitting signals across the membrane.
    • Agonists bind to receptors, causing a conformational change that activates the receptor and triggers a response.
    • Binding specificity and affinity between ligands and receptors are determined by the shape and chemical properties of the ligand and the binding site on the receptor.

    Signaling Pathways

    • A given ligand binding to different types of receptors can activate different responses in a cell.
    • The intracellular domain of membrane receptors is responsible for transmitting the signal to the interior of the cell.
    • Antagonists bind to receptors, blocking the binding of agonists and preventing the activation of the receptor.

    G Protein-Coupled Receptors (GPCRs)

    • GPCRs are a type of membrane receptor that play a crucial role in cell signaling.
    • GPCRs have an extracellular ligand-binding domain, a transmembrane domain, and an intracellular domain that interacts with G proteins.
    • G proteins are heterotrimeric proteins consisting of α, β, and γ subunits.
    • The main role of GPCRs in cell signaling is to transmit signals from extracellular ligands to intracellular effectors.

    G Protein Signaling

    • GPCR signaling involves the activation of G proteins, which in turn activate downstream effectors.
    • The localization of GPCRs and transducers/effectors can affect the signaling pathway.
    • Physiological responses controlled by activation of signaling pathways include vision, smell, taste, and hormone regulation.
    • Insulin primarily regulates glucose metabolism.

    G Protein Subunits

    • There are several types of alpha Gα subunits, including Gαs, Gαi, and Gαq.
    • The alpha subunit designated as Gs activates adenylate cyclase.
    • There are several types of beta Gβ subunits.
    • Different combinations of G protein subunits can form, leading to diverse signaling pathways.

    Regulators of G-Protein Signaling (RGS)

    • RGS proteins are negative regulators of G protein signaling.
    • RGS domain-containing proteins promote GTP hydrolysis by the α-subunit of heterotrimeric G proteins.
    • There are several RGS proteins identified in humans.

    GPCR Structure

    • The topology of class A and class B receptors differs, with class A having a more compact structure.
    • The 3D structure of bRho in its inactive state was first revealed in 2000.
    • The "venus flytrap domain" is the part of the GPCR that contains the entire ligand binding site.

    GPCR Families

    • The family of GPCRs that comprises fifteen receptors in humans and is activated by small molecules such as amino acids is the glutamate receptor family.
    • The GPCR family that includes receptors for neurotransmitters and is classified into rhodopsin and nonrhodopsin receptors is the Class A GPCR family.
    • The class of GPCR-ligand complexes that presents diverse ligand-binding sites for small molecules such as amino acids is the Class B GPCR family.

    GPCR-Ligand Complexes

    • The representative structure from Class B GPCR-ligand complexes is bound to negative allosteric modulators.
    • The PDB ID associated with the representative structure from Class B GPCR-ligand complexes, CRF1, is 4KVM.

    GPCR Structural Biology

    • The pioneering study of the 2D structure for bovine rhodopsin marked the beginning of GPCR structural biology.
    • The 3D structure of GPCRs remained challenging to determine despite relentless efforts.
    • Electron cryomicroscopy was used to study the structure of GPCRs.
    • HA-TAG proteins form complexes with G protein subunits.

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    Chrivia GPCR Lectures 1 2024 PDF

    Description

    Test your knowledge on cell signaling, G protein-coupled receptors, signal transduction, and intracellular components involved in cellular response. Explore the properties of signaling molecules, cell-surface receptors, and the G protein cycle of reactions in GPCR signaling.

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