G-Protein Coupled Receptors (GPCRs) in Eukaryotes
28 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Where are G-protein coupled receptors typically found?

  • Viruses
  • Prokaryotes
  • Eukaryotes (correct)
  • Fungi

    • What percentage of modern medicinal drugs target GPCRs?

  • 30 to 50% (correct)
  • 10 to 20%
  • 50 to 70%
  • 20 to 30%

    • What is unique about the structure of GPCRs?

  • They have nine transmembrane alpha sheets
  • They have seven transmembrane alpha helices (correct)
  • They have three transmembrane beta helices
  • They have five transmembrane beta sheets

    • What is another name for GPCRs based on their structure?

    <p>7 transmembrane receptors</p> Signup and view all the answers

    What is the function of GPCRs in the body?

    <p>They regulate a variety of physiological processes</p> Signup and view all the answers

    What type of compounds can bind to GPCRs?

    <p>A wide range of compounds, including light sensitive compounds, odors, pheromones, hormones, and neurotransmitters</p> Signup and view all the answers

    What is the significance of GPCRs in research?

    <p>Many G-proteins and GPCRs still have unknown functions</p> Signup and view all the answers

    What award was given for research on GPCRs in 2012?

    <p>Nobel Prize in Chemistry</p> Signup and view all the answers

    What is the primary function of G-proteins?

    <p>To bind GTP and GDP</p> Signup and view all the answers

    What is the composition of G-proteins associated with GPCRs?

    <p>Heterotrimeric (three subunits)</p> Signup and view all the answers

    What is the purpose of lipid anchors in G-proteins?

    <p>To attach to the cell membrane</p> Signup and view all the answers

    What is the result of a G-protein binding GTP?

    <p>The G-protein dissociates from the beta and gamma subunits</p> Signup and view all the answers

    What is the role of the GPCR in the signaling pathway?

    <p>To respond to signaling molecules</p> Signup and view all the answers

    What is the result of the ligand binding to the GPCR?

    <p>The GPCR undergoes a conformational change</p> Signup and view all the answers

    What is the function of the alpha subunit in the signaling pathway?

    <p>To exchange GDP for GTP</p> Signup and view all the answers

    What is the purpose of the beta and gamma subunits in the signaling pathway?

    <p>To form a dimer with the alpha subunit</p> Signup and view all the answers

    What is the ultimate outcome of the G-protein signaling pathway?

    <p>The alpha subunit regulates protein function</p> Signup and view all the answers

    What is the order of the steps in the G-protein signaling pathway?

    <p>Ligand binds to GPCR, GPCR undergoes conformational change, alpha subunit exchanges GDP for GTP, alpha subunit dissociates and regulates target proteins</p> Signup and view all the answers

    What occurs when the alpha subunit binds to a target protein?

    <p>The target protein relays a signal</p> Signup and view all the answers

    What is the result of the hydrolysis of GTP to GDP?

    <p>The process returns to its normal state</p> Signup and view all the answers

    What is the role of the RGS protein?

    <p>To accelerate the hydrolysis of GTP to GDP</p> Signup and view all the answers

    What is the function of adenylate cyclase?

    <p>To produce cAMP from ATP</p> Signup and view all the answers

    What is the effect of cyclic AMP on the body?

    <p>It increases heart rate and dilates skeletal muscle blood vessels</p> Signup and view all the answers

    What happens to the alpha subunit when the GTP is hydrolyzed to GDP?

    <p>It returns to its original state</p> Signup and view all the answers

    What is the role of the beta-gamma subunits?

    <p>To interact with other proteins to relay messages</p> Signup and view all the answers

    What is the result of the binding of epinephrine to the adrenergic receptor?

    <p>The GPCR undergoes a conformational change</p> Signup and view all the answers

    What is the purpose of the G-protein signaling pathway?

    <p>To transmit signals from outside the cell to inside the cell</p> Signup and view all the answers

    What is the final result of the G-protein signaling pathway?

    <p>The transmission of signals from outside the cell to inside the cell</p> Signup and view all the answers

    Study Notes

    G-Protein Coupled Receptors (GPCRs)

    • GPCRs are only found in eukaryotes and comprise the largest known class of membrane receptors.
    • There are over 1,000 known different types of GPCRs in humans, each specific to a particular function.

    Structure of GPCRs

    • GPCRs have seven transmembrane alpha helices, which is a unique and important characteristic.
    • They are often also referred to as "7 transmembrane receptors" due to this structural feature.

    Interaction with G-Proteins

    • GPCRs interact with G-proteins, which are specialized proteins that can bind GTP and GDP.
    • The G-proteins that associate with GPCRs are heterotrimeric, meaning they have three different subunits: alpha, beta, and gamma.

    Signaling Pathway

    • The signaling pathway of GPCRs involves a ligand binding to the receptor, causing a conformational change.
    • The conformational change triggers the exchange of GDP for GTP on the alpha subunit, which then dissociates and regulates target proteins.
    • The alpha subunit and beta-gamma dimer can interact with other proteins to relay messages, leading to a range of downstream effects.

    Steps of the Signaling Pathway

    • Step 1: Ligand binds to the GPCR
    • Step 2: GPCR undergoes a conformational change
    • Step 3: Alpha subunit exchanges GDP for GTP
    • Step 4: Alpha subunit dissociates and regulates target proteins
    • Step 5: Target protein relays a signal, leading to a range of downstream effects
    • Step 6: GTP is hydrolyzed to GDP, returning the system to its original state

    Regulation of G-Protein Signaling

    • The system can be regulated by RGS proteins, which accelerate the hydrolysis of GTP to GDP.

    Example of GPCR Function

    • The binding of epinephrine (adrenaline) to an adrenergic receptor (a type of GPCR) triggers a signaling pathway that leads to an increase in heart rate, dilation of skeletal muscle blood vessels, and breakdown of glycogen to glucose.

    Importance of GPCRs

    • GPCRs are a large and diverse family of cell surface receptors that respond to many different external signals.
    • They play a crucial role in regulating a wide range of bodily functions, including sensation, growth, and hormone response.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Learn about G-protein coupled receptors, their structure, function, and importance in medicinal drugs. Found only in eukaryotes, they comprise the largest class of membrane receptors.

    More Like This

    G Protein Coupled Receptors (GPCRs)
    29 questions

    G Protein Coupled Receptors (GPCRs)

    MagicalHeliodor avatar
    MagicalHeliodor
    G Protein Coupled Receptors (GPCRs)
    16 questions

    G Protein Coupled Receptors (GPCRs)

    ClearerBeech avatar
    ClearerBeech
    Neurobiology G-Protein Coupled Receptors
    36 questions

    Neurobiology G-Protein Coupled Receptors

    KindlyElegy avatar
    KindlyElegy
    G Protein-Coupled Receptors Overview
    34 questions

    G Protein-Coupled Receptors Overview

    OptimisticUnity8791 avatar
    OptimisticUnity8791
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser