Podcast
Questions and Answers
What is the main function of guanylyl cyclase in its receptor form?
What is the main function of guanylyl cyclase in its receptor form?
- Dimerize with other receptors
- Convert ATP to cAMP
- Convert GTP to cGMP (correct)
- Phosphorylate serine and threonine residues
What causes the activation of receptor guanylyl cyclase?
What causes the activation of receptor guanylyl cyclase?
- Binding of TGFß
- Binding of ANP (correct)
- Binding of growth factors
- Binding of insulin
What do receptor serine/threonine kinases primarily phosphorylate?
What do receptor serine/threonine kinases primarily phosphorylate?
- GTP to cGMP
- Serine and threonine residues on target proteins (correct)
- cAMP to AMP
- Tyrosine residues on receptor proteins
What initiates the MAP kinase signalling pathway?
What initiates the MAP kinase signalling pathway?
Which receptors are involved in insulin-mediated glucose uptake?
Which receptors are involved in insulin-mediated glucose uptake?
What is the role of phosphotyrosine motifs created by receptor tyrosine kinases?
What is the role of phosphotyrosine motifs created by receptor tyrosine kinases?
What is the effect of atrial natriuretic peptide (ANP) when signaling through guanylyl cyclase?
What is the effect of atrial natriuretic peptide (ANP) when signaling through guanylyl cyclase?
Which type of receptor is formed by the dimerization of two molecules of insulin?
Which type of receptor is formed by the dimerization of two molecules of insulin?
What initiates the mechanism of signalling for receptor tyrosine phosphatase?
What initiates the mechanism of signalling for receptor tyrosine phosphatase?
Which of the following best describes the role of tyrosine phosphatase activity in receptor signalling?
Which of the following best describes the role of tyrosine phosphatase activity in receptor signalling?
What is a distinctive feature of receptor tyrosine kinases compared to G protein-coupled receptors?
What is a distinctive feature of receptor tyrosine kinases compared to G protein-coupled receptors?
In the context of signalling pathways, what is a primary function of CD45?
In the context of signalling pathways, what is a primary function of CD45?
How do GPCRs primarily relay their signals?
How do GPCRs primarily relay their signals?
What is the main difference in signal duration between GPCRs and RTKs?
What is the main difference in signal duration between GPCRs and RTKs?
What common outcome do both GPCRs and RTKs achieve in their signalling pathways?
What common outcome do both GPCRs and RTKs achieve in their signalling pathways?
What type of receptors do not require dimerization for their activation?
What type of receptors do not require dimerization for their activation?
What is the main effect of cholera toxin on the Ga subunit?
What is the main effect of cholera toxin on the Ga subunit?
Which of the following statements about the action of G proteins is incorrect?
Which of the following statements about the action of G proteins is incorrect?
What is the main physiological effect of increased levels of cAMP and PKA due to pertussis toxin acting on G proteins?
What is the main physiological effect of increased levels of cAMP and PKA due to pertussis toxin acting on G proteins?
What is the function of adenylyl cyclase in the G protein signaling pathway?
What is the function of adenylyl cyclase in the G protein signaling pathway?
Which subtypes of muscarinic receptors are classified as Gq-coupled stimulatory receptors?
Which subtypes of muscarinic receptors are classified as Gq-coupled stimulatory receptors?
What is the consequence of activating protein kinase A (PKA) after cAMP binding?
What is the consequence of activating protein kinase A (PKA) after cAMP binding?
Which receptors are known to couple with Gs subunits?
Which receptors are known to couple with Gs subunits?
What is the primary role of phospholipase C (PLC) in signal transduction?
What is the primary role of phospholipase C (PLC) in signal transduction?
How does pertussis toxin affect the Gi subunit?
How does pertussis toxin affect the Gi subunit?
Which response is mediated by G proteins containing the alphaq11 subunit in acetylcholine signaling?
Which response is mediated by G proteins containing the alphaq11 subunit in acetylcholine signaling?
What happens to IP3 after it functions in signaling within the cytosol?
What happens to IP3 after it functions in signaling within the cytosol?
Which of the following describes the role of G proteins in cellular signaling?
Which of the following describes the role of G proteins in cellular signaling?
What is the role of cAMP in the signaling pathway activated by GPCR?
What is the role of cAMP in the signaling pathway activated by GPCR?
What autonomic effects are primarily associated with muscarinic receptors?
What autonomic effects are primarily associated with muscarinic receptors?
What is the role of DAG in the signaling process following the action of phospholipase C?
What is the role of DAG in the signaling process following the action of phospholipase C?
How does activation of M3 receptors by alphaq11-containing G proteins affect respiratory function?
How does activation of M3 receptors by alphaq11-containing G proteins affect respiratory function?
What initiates the activation of phospholipase Cß?
What initiates the activation of phospholipase Cß?
What is the primary function of calmodulin in cellular signaling?
What is the primary function of calmodulin in cellular signaling?
Why does diacylglycerol (DAG) remain in the plasma membrane?
Why does diacylglycerol (DAG) remain in the plasma membrane?
What intracellular responses do calmodulin kinases (CaMKs) mediate?
What intracellular responses do calmodulin kinases (CaMKs) mediate?
What effect does activated protein kinase C (PKC) have on cells?
What effect does activated protein kinase C (PKC) have on cells?
How does IP3 facilitate the release of calcium ions into the cytosol?
How does IP3 facilitate the release of calcium ions into the cytosol?
What is the mechanism through which alpha1 adrenergic receptors induce vasoconstriction?
What is the mechanism through which alpha1 adrenergic receptors induce vasoconstriction?
Which component serves as the most critical calcium-binding protein mediating intracellular responses?
Which component serves as the most critical calcium-binding protein mediating intracellular responses?
What is the primary function of Ras-GEF in the activation of Ras?
What is the primary function of Ras-GEF in the activation of Ras?
Which statement correctly describes the role of adaptor proteins in RAS activation?
Which statement correctly describes the role of adaptor proteins in RAS activation?
In the MAPK signaling cascade, what is the primary role of MAPKKK?
In the MAPK signaling cascade, what is the primary role of MAPKKK?
What occurs once the Ras protein is activated?
What occurs once the Ras protein is activated?
How are tyrosine kinases activated in tyrosine kinase-associated receptors?
How are tyrosine kinases activated in tyrosine kinase-associated receptors?
What do activated tyrosine kinases do in this signaling mechanism?
What do activated tyrosine kinases do in this signaling mechanism?
Which function explains the role of phosphotyrosine motifs in signaling by tyrosine kinase-associated receptors?
Which function explains the role of phosphotyrosine motifs in signaling by tyrosine kinase-associated receptors?
Which kinase is typically referred to as the third kinase in the MAPK signaling cascade?
Which kinase is typically referred to as the third kinase in the MAPK signaling cascade?
Flashcards
What triggers the activation of a G protein?
What triggers the activation of a G protein?
The exchange of GDP for GTP on the alpha subunit of the G protein, leading to its activation.
What is a G-protein coupled receptor (GPCR)?
What is a G-protein coupled receptor (GPCR)?
A type of receptor that uses a G protein to relay signals within the cell.
What is a second messenger?
What is a second messenger?
A molecule that acts as a messenger inside the cell, relaying signals from the GPCR.
What does the Ga-GTP subunit do?
What does the Ga-GTP subunit do?
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What is adenylyl cyclase?
What is adenylyl cyclase?
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How does cholera toxin (CTx) affect the G protein?
How does cholera toxin (CTx) affect the G protein?
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What is Gi?
What is Gi?
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How does pertussis toxin affect the Gi subunit?
How does pertussis toxin affect the Gi subunit?
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G protein containing alphaq11 subunits
G protein containing alphaq11 subunits
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Muscarinic receptors
Muscarinic receptors
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Phospholipase C (PLC)
Phospholipase C (PLC)
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Inositol trisphosphate (IP3)
Inositol trisphosphate (IP3)
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Diacylglycerol (DAG)
Diacylglycerol (DAG)
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Protein kinase C (PKC)
Protein kinase C (PKC)
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Gq signaling pathway
Gq signaling pathway
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Calcium signaling
Calcium signaling
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What are receptor guanylyl cyclases?
What are receptor guanylyl cyclases?
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Explain the signaling mechanism of receptor guanylyl cyclases.
Explain the signaling mechanism of receptor guanylyl cyclases.
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What is generated by the guanylyl cyclase activity of the receptor?
What is generated by the guanylyl cyclase activity of the receptor?
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What is the effect of ANP signaling via guanylyl cyclase?
What is the effect of ANP signaling via guanylyl cyclase?
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Describe receptor serine/threonine kinases.
Describe receptor serine/threonine kinases.
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Explain the signaling mechanism of receptor serine/threonine kinases.
Explain the signaling mechanism of receptor serine/threonine kinases.
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Describe receptor tyrosine kinases (RTKs).
Describe receptor tyrosine kinases (RTKs).
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Explain the mechanism of signaling for receptor tyrosine kinases.
Explain the mechanism of signaling for receptor tyrosine kinases.
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What is IP3 and what does it do?
What is IP3 and what does it do?
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What allows the release of Ca2+ into the cytosol?
What allows the release of Ca2+ into the cytosol?
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What transports Ca2+ back into the ER?
What transports Ca2+ back into the ER?
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What is the most important calcium-binding protein involved in intracellular responses?
What is the most important calcium-binding protein involved in intracellular responses?
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What does the Ca2+-CaM complex activate?
What does the Ca2+-CaM complex activate?
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What do calmodulin kinases (CaMKs) do?
What do calmodulin kinases (CaMKs) do?
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What are the effects of DAG and how does it work?
What are the effects of DAG and how does it work?
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How does PKC interact with IP3 signaling?
How does PKC interact with IP3 signaling?
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Cytokine Signalling Pathway
Cytokine Signalling Pathway
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Receptor Tyrosine Phosphatases (RTPs)
Receptor Tyrosine Phosphatases (RTPs)
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RTP Signalling Mechanism
RTP Signalling Mechanism
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Function of RTP Activity
Function of RTP Activity
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RTPs and Downstream Phosphorylation
RTPs and Downstream Phosphorylation
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Example: CD45 and Lymphocyte Maturation
Example: CD45 and Lymphocyte Maturation
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GPCRs vs. RTKs: Structure
GPCRs vs. RTKs: Structure
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GPCRs vs. RTKs: Enzymatic Activity
GPCRs vs. RTKs: Enzymatic Activity
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Adaptor Protein Role in Ras Activation
Adaptor Protein Role in Ras Activation
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How does RAS-GEF Activate Ras?
How does RAS-GEF Activate Ras?
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Activated Ras: Function and Localization
Activated Ras: Function and Localization
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MAPKKK: The Initiator
MAPKKK: The Initiator
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MAPKK: The Middleman
MAPKK: The Middleman
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MAPK: The Messenger
MAPK: The Messenger
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Tyrosine Kinase-Associated Receptors
Tyrosine Kinase-Associated Receptors
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Signaling Mechanism of Tyrosine Kinase-Associated Receptors
Signaling Mechanism of Tyrosine Kinase-Associated Receptors
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Study Notes
Receptor Types and Signaling Mechanisms
- Four main receptor classes: ligand-gated ion channels, G-protein coupled receptors (GPCRs), enzyme-linked receptors, and nuclear receptors.
- G-protein activation: GPCR activation triggers GDP-GTP exchange on the G protein alpha subunit. The alpha-GTP subunit dissociates from the beta-gamma complex, activating downstream effectors.
- Adenylyl cyclase (AC) activation: Activated G protein (Gas) stimulates AC, converting ATP to cAMP (a second messenger).
- Protein Kinase A (PKA) activation: cAMP binds to PKA's regulatory subunits, releasing the catalytic subunits, which become active.
- Cholera toxin (CTx) effect: CTx ADP-ribosylates the Gas subunit, preventing GTP hydrolysis; leading to sustained cAMP production and diarrhea.
- Pertussis toxin (PTx) effect: PTx ADP-ribosylates Gai, preventing its inhibitory action on AC, leading to increased cAMP and whooping cough symptoms.
- Gq/11 protein activation: Gq/11 activates phospholipase C (PLC), cleaving PIP2 into IP3 and DAG.
- IP3 function: IP3 releases calcium from the endoplasmic reticulum (ER) into the cytoplasm.
- DAG function: DAG activates protein kinase C (PKC) in the membrane.
- Calcium signaling: Calcium acts as a second messenger; CaM (calmodulin) binds to calcium, activating CaMKs (calmodulin kinases).
- Calmodulin kinases (CaMKs): CaMKs phosphorylate target proteins, influencing various cellular responses, including smooth muscle contraction.
- Alpha1-adrenergic receptor function: Gq-coupled, increasing intracellular calcium leading to vasoconstriction.
- Beta2-adrenergic receptor function: Gs-coupled, increasing cAMP, leading to vasodilation.
Enzyme-Linked Receptors
- Receptor guanylyl cyclases: Convert GTP to cGMP, activating downstream kinases. ANP (atrial natriuretic peptide) is an example.
- Receptor serine/threonine kinases: Phosphorylate target proteins (e.g., SMAD proteins), mediating responses like cell proliferation.
- Receptor tyrosine kinases (RTKs): Phosphorylate themselves and other proteins, initiating phosphorylation cascades. Examples include insulin signaling.
- Tyrosine kinase-associated receptors: Lack intrinsic kinase activity but associate with cytoplasmic kinases (e.g., JAK2), triggering similar phosphorylation cascades. Examples include signaling by cytokines.
- Receptor tyrosine phosphatases: Dephosphorylate target proteins, modulating cellular activity by reversing phosphorylation events initiated by other receptors. Examples include lymphocytes maturation (activation of CD45)
GPCRs vs. RTKs
- GPCRs: 7 transmembrane helices; no intrinsic enzymatic activity; signal relayed via secondary messengers (e.g., cAMP, IP3/DAG); shorter duration of signaling.
- RTKs: Single transmembrane helix; intrinsic enzymatic activity; signal relayed via phosphorylation cascades; longer signaling duration.
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