CaMKII Function and Structure Quiz
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What role does CaMKII primarily play in the brain?

  • Regulates blood flow in neurons
  • Serves as a neurotransmitter
  • Facilitates the release of ATP
  • Acts as a gate for catalytic enzyme activity (correct)

    • Which of the following subunit combinations predominantly compose CaMKII in the brain?

  • α and δ
  • β and δ
  • β and γ
  • α and β (correct)

    • How many isoforms of CaMKII exist, and from how many genes are they derived?

  • 28 isoforms from 4 genes (correct)
  • 16 isoforms from 2 genes
  • 12 isoforms from 3 genes
  • 32 isoforms from 5 genes

    • What structural feature allows CaMKII to form a non-dissociable holoenzyme?

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

    In reference to the structure of CaMKII, how are the catalytic/regulatory domains organized?

    <p>As two hexameric rings</p> Signup and view all the answers

    Which of the following statements about CaMKII's interaction with anchoring proteins is true?

    <p>It directs targeting to specific intracellular sites.</p> Signup and view all the answers

    What is the length of the narrow stalk that links the hexameric rings in the CaMKII structure?

    <p>Highly variable</p> Signup and view all the answers

    What maintains the CaMKII enzyme in an active state even after the dissociation of Calmodulin?

    <p>Phosphorylation of the Thr286 site by a neighboring subunit</p> Signup and view all the answers

    Which component is NOT involved in keeping the gate open for CaMKII?

    <p>Calmodulin binding</p> Signup and view all the answers

    In the context of CaMKII activation, what characterizes brief activation?

    <p>No autophosphorylation</p> Signup and view all the answers

    What role does the autoinhibitory domain play in CaMKII activation?

    <p>It cannot inhibit the S site and allows the kinase to remain active</p> Signup and view all the answers

    What can achieve the opening of the gate in CaMKII for continued activation?

    <p>Binding of the T site specifically to the NR2B subunit</p> Signup and view all the answers

    Which activation mechanism for CaMKII is characterized by inter-subunit interaction?

    <p>Phosphorylation through neighboring subunits</p> Signup and view all the answers

    What is the effect of phosphorylation at the Thr286 site with respect to the autoinhibitory domain?

    <p>It prevents the autoinhibitory domain from inhibiting the S site</p> Signup and view all the answers

    Which statement differentiates autophosphorylation from phosphorylation by a neighboring subunit in CaMKII activation?

    <p>Phosphorylation by neighboring subunits can lead to brief activation.</p> Signup and view all the answers

    Which mechanism disrupts the function of the voltage-dependent K+ channel KCNQ2, thus increasing neuronal excitability?

    <p>Modification of potassium channel activity</p> Signup and view all the answers

    What feature characterizes Immediate Early Genes (IEGs)?

    <p>Induced rapidly by pre-existing transcription factors</p> Signup and view all the answers

    In the context of neuronal gene expression, what is the primary role of IEGs?

    <p>Triggering cascades of activity-dependent neuronal gene expression</p> Signup and view all the answers

    Which of the following is NOT considered an Immediate Early Gene?

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

    What is the relationship between the activation of IEG-expressing neurons and memory recall?

    <p>Reactivation of IEG-expressing neurons triggers memory recall</p> Signup and view all the answers

    What is a primary role of CREB in neuronal function?

    <p>Facilitating long-term potentiation and synaptic capture</p> Signup and view all the answers

    What defines the short half-life of IEGs in neuronal activity?

    <p>Rapid degradation following transcription</p> Signup and view all the answers

    Which of the following options is associated with the concept of engrams in memory?

    <p>Engrams represent physical changes in the brain due to experience</p> Signup and view all the answers

    What type of channels does the disruption of KCNQ2 primarily affect?

    <p>Potassium channels</p> Signup and view all the answers

    Which is a characteristic feature of the immediate response of IEGs to neurotransmitters?

    <p>Responds without needing new protein synthesis</p> Signup and view all the answers

    What is the primary function of endogenous Arc protein as described in the context provided?

    <p>To mediate intercellular transfer of mRNA in neurons</p> Signup and view all the answers

    Which role does BDNF play in the context of learning and memory processes?

    <p>It is necessary for the induction of long-term potentiation (LTP)</p> Signup and view all the answers

    What is the significance of PKMζ in relation to long-term potentiation (LTP)?

    <p>It is constitutively active and plays a role in LTP maintenance</p> Signup and view all the answers

    Which BDNF functions are highlighted in the context of neuronal development?

    <p>Regulating axon pathfinding and synapse formation</p> Signup and view all the answers

    What similarity does Arc protein share with retroviral proteins as stated in the content?

    <p>Arc exhibits biochemical properties similar to Gag proteins</p> Signup and view all the answers

    What is the primary role of CREB in relation to memory?

    <p>Facilitating long-term memory formation</p> Signup and view all the answers

    Which of the following isoforms of CREB is mentioned as an inhibitor?

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

    What effect does increased CREB activity have on synaptic excitability?

    <p>Increases intrinsic excitability</p> Signup and view all the answers

    Which experimental form of plasticity is indicated to bypass the requirement for CREB?

    <p>Strong theta burst stimulation</p> Signup and view all the answers

    What observation was made regarding mice with disrupted CREB activity?

    <p>They are impaired in long-term fear conditioning</p> Signup and view all the answers

    What was the outcome of expressing the constitutively active form of CREB in forebrain neurons?

    <p>Increased expression of CREB-dependent genes</p> Signup and view all the answers

    Which method was used to express VP16-CREB in the study?

    <p>tTA system</p> Signup and view all the answers

    What happens to fear training-induced phosphorylation of CREB?

    <p>Increases with time post-training</p> Signup and view all the answers

    In the context of memory expression, what does the ablation of LA neurons overexpressing CREB lead to?

    <p>Complete blockade of memory expression</p> Signup and view all the answers

    What does the study suggest about the relationship between CREB overexpression and memory potentiation?

    <p>It mimics the effects of intrinsic excitability</p> Signup and view all the answers

    What is the relationship between c-fos KO and structural plasticity in the hippocampus following seizures?

    <p>c-fos KO impairs structural plasticity.</p> Signup and view all the answers

    Which function is primarily associated with the Arc protein in dendrites after stimulation?

    <p>Transports mRNA to activated dendritic domains.</p> Signup and view all the answers

    How does the movement speed of Arc mRNA in dendrites following stimulation compare to other cellular processes?

    <p>Rapid, traveling at approximately 300μm/hr.</p> Signup and view all the answers

    What characteristic of IEGs supports their definition and function in neuronal activity?

    <p>They are rapidly induced following neuronal activity.</p> Signup and view all the answers

    In the context of learning and memory, how do IEGs contribute to long-term potentiation (LTP)?

    <p>They are essential for the formation of engrams.</p> Signup and view all the answers

    What structural organization is unique to the catalytic/regulatory domains of CaMKII?

    <p>They form two hexameric rings linked by a stalk.</p> Signup and view all the answers

    Which isoforms of CaMKII are predominantly found in the brain?

    <p>α and β</p> Signup and view all the answers

    What critical feature enables the non-dissociable holoenzyme formation of CaMKII?

    <p>The association domain linking subunits.</p> Signup and view all the answers

    Which of the following best describes the composition of a CaMKII holoenzyme?

    <p>It consists of twelve subunits forming two hexameric rings.</p> Signup and view all the answers

    How does the autoinhibitory domain influence CaMKII activity?

    <p>It inhibits the catalytic enzyme's activity.</p> Signup and view all the answers

    Which domains are critical for the interaction of CaMKII with intracellular sites?

    <p>Stalk and association domains.</p> Signup and view all the answers

    What role does the enzyme CaMKII primarily serve in relation to synaptic functions?

    <p>It regulates synaptic plasticity and memory formation.</p> Signup and view all the answers

    What is required for the CaMKII to remain active after Calmodulin dissociation?

    <p>Phosphorylation of Thr286 by a neighboring subunit</p> Signup and view all the answers

    Which of the following accurately describes the role of the T site in CaMKII activation?

    <p>It interacts with the NR2B subunit of NMDAR</p> Signup and view all the answers

    What characterizes the autophosphorylation process in CaMKII?

    <p>It is absent during brief activation</p> Signup and view all the answers

    Which condition can lead to the inactivation of CaMKII?

    <p>Autoinhibition through the autoinhibitory domain</p> Signup and view all the answers

    How does the binding of T side contribute to CaMKII functionality?

    <p>It opens the gate allowing continued activation</p> Signup and view all the answers

    What best explains why CaMKII remains active despite autoinhibitory mechanisms?

    <p>It undergoes conformational changes upon T site binding</p> Signup and view all the answers

    Why is phosphorylation at the Thr286 site critical for CaMKII activity?

    <p>It sustains the enzyme's active state</p> Signup and view all the answers

    What does the term 'opening of the gate' in the context of CaMKII refer to?

    <p>The transition from an inactive to an active state</p> Signup and view all the answers

    Which statement is true about the relationship between Thr286 phosphorylation and CaMKII's autoinhibitory domain?

    <p>Thr286 phosphorylation disables the autoinhibitory domain</p> Signup and view all the answers

    What triggers the transition from short-term to long-term persistent activation of CaMKII?

    <p>A specific threshold of kinase site phosphorylation</p> Signup and view all the answers

    What happens to the activity of CaMKII when Thr286 is dephosphorylated?

    <p>The activity gradually declines</p> Signup and view all the answers

    What effect does active CaMKII have on CA1 pyramidal cells?

    <p>Increases the amplitude of spontaneous synaptic potentials</p> Signup and view all the answers

    What leads to the occlusion of CaMKII-induced potentiation and LTP induction?

    <p>Increased transmission in the non-LTP group</p> Signup and view all the answers

    Which mechanism allows CaMKII to maintain its activity despite the rapid dissociation of calmodulin?

    <p>Autophosphorylation at Thr286</p> Signup and view all the answers

    During short-term persistent activation, how does the autophosphorylation of Thr286 affect CaMKII?

    <p>It allows for transient activity</p> Signup and view all the answers

    Which condition must be met for sustained long-term potentiation (LTP) to occur?

    <p>The rate of autophosphorylation must exceed dephosphorylation rate</p> Signup and view all the answers

    What is one consequence of LTP regarding CaMKII activity?

    <p>CaMKII activity enhances synaptic transmission through the same mechanism</p> Signup and view all the answers

    Why is the 'on' state of CaMKII considered long-lasting once achieved?

    <p>Because the kinase operates faster than the phosphatase</p> Signup and view all the answers

    What effect does the inhibition of CREB lead to in terms of memory outcomes?

    <p>Long-term memory deficits only</p> Signup and view all the answers

    Which of the following genes is NOT related to the CREB family of transcription factors?

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

    How does increased CREB activity influence synaptic changes?

    <p>Increases the expression of CREB-dependent genes</p> Signup and view all the answers

    What is the immediate consequence of fear training on CREB activity?

    <p>CREB is phosphorylated</p> Signup and view all the answers

    What neural aspect does the ablation of LA neurons overexpressing CREB affect?

    <p>Memory formation</p> Signup and view all the answers

    Which form of LTP is less likely to be impaired when CREB is inhibited?

    <p>Early long-term potentiation (E-LTP)</p> Signup and view all the answers

    What is a distinguishing feature of VP16-CREB compared to conventional CREB?

    <p>It is a constitutively active form of CREB</p> Signup and view all the answers

    What is indicated by the expression of KCREB in transgenic mice?

    <p>Inhibition of specific CREB-dependent pathways</p> Signup and view all the answers

    Which physiological process is explicitly indicated to be enhanced by increased CREB activity?

    <p>Long-term memory consolidation</p> Signup and view all the answers

    What outcome is most likely associated with mice showing disrupted CREB activity in memory tasks?

    <p>Impaired long-term fear conditioning</p> Signup and view all the answers

    Which subunit classification primarily represents the isoforms of CaMKII found in the brain?

    <p>Alpha and beta</p> Signup and view all the answers

    What structural feature facilitates CaMKII's activity modulation through Ca2+/calmodulin?

    <p>The autoinhibitory domain</p> Signup and view all the answers

    Which mechanism is essential for CaMKII to maintain its active state after dissociation from its activating partner?

    <p>Phosphorylation at the Thr286 site</p> Signup and view all the answers

    What defines the role of the narrow stalk in the CaMKII structure?

    <p>It connects the hexameric rings.</p> Signup and view all the answers

    Which aspect of CaMKII's structure contributes to its ability to form a non-dissociable holoenzyme?

    <p>The association domain's interaction with catalytic sites</p> Signup and view all the answers

    What is the significance of the regulatory domains in CaMKII's structure?

    <p>To inhibit CaMKII activity</p> Signup and view all the answers

    Which property of CaMKII is most directly influenced by the presence of its 28 isoforms?

    <p>The diversity of cellular signaling responses</p> Signup and view all the answers

    What is a significant role of Arc protein in dendrites following stimulation?

    <p>It enhances the structural plasticity by co-precipitating with F-actin.</p> Signup and view all the answers

    How does c-fos knockout (KO) affect structural plasticity in the hippocampus?

    <p>It impairs the sprouting of mossy fiber axons after seizures.</p> Signup and view all the answers

    What is the primary mechanism of Arc mRNA movement in dendrites after neuronal stimulation?

    <p>Arc mRNA travels at a speed of approximately 300μm/hr throughout the dendrites.</p> Signup and view all the answers

    What component is essential for immediate early gene (IEG) function in neuronal activity?

    <p>Rapid transcription following synaptic activation.</p> Signup and view all the answers

    What structural effect does the presence of Arc protein have on dendrites?

    <p>Promotion of actin filament assembly in activated dendritic regions.</p> Signup and view all the answers

    What must occur for the kinase CaMKII to remain active even after the dissociation of Calmodulin?

    <p>Binding of T side to the NMDAR NR2B subunit</p> Signup and view all the answers

    Which result occurs when the autoinhibitory domain of CaMKII does not inhibit the S site?

    <p>The kinase remains active</p> Signup and view all the answers

    What type of activation of CaMKII is characterized by the absence of autophosphorylation?

    <p>Brief activation</p> Signup and view all the answers

    What is the primary mechanism for maintaining the gate open in CaMKII activation?

    <p>Phosphorylation of the Thr286 site by a neighboring subunit</p> Signup and view all the answers

    What characterizes the mechanism of opening the gate of CaMKII?

    <p>Phosphorylation and binding can individually maintain activity</p> Signup and view all the answers

    In what circumstance would the CaMKII enzyme become inactive?

    <p>Loss of binding to the NMDAR NR2B subunit</p> Signup and view all the answers

    What does the absence of necessary phosphorylation at the Thr286 site lead to?

    <p>CaMKII remains in a non-active state</p> Signup and view all the answers

    Which statement is true regarding the relationship between the autoinhibitory domain and CaMKII activity?

    <p>Its inhibition prevents sustained activity</p> Signup and view all the answers

    What effect does the binding of the T side to the NMDAR have on CaMKII?

    <p>It facilitates a conformational change that keeps the gate open</p> Signup and view all the answers

    What leads to the long-term persistent activation of CaMKII following LTP?

    <p>The rate of autophosphorylation exceeding dephosphorylation</p> Signup and view all the answers

    Which mechanism ensures the sustained active state of CaMKII after Calmodulin dissociates?

    <p>Autophosphorylation at Thr286</p> Signup and view all the answers

    What is characteristic of the 'on' state of the switch based on CaMKII activation?

    <p>It can last for an extended period once initiated</p> Signup and view all the answers

    What initiates the short-term persistent activation of CaMKII?

    <p>Autophosphorylation at Thr286</p> Signup and view all the answers

    During the process of LTP, what must occur for CaMKII activity to enhance synaptic transmission?

    <p>Autophosphorylation must exceed dephosphorylation rates</p> Signup and view all the answers

    What effect does perfusion of active CaMKII on CA1 pyramidal cells have?

    <p>It increases the amplitude of spontaneous synaptic potentials</p> Signup and view all the answers

    What role does Thr286 phosphorylation play in the activity of CaMKII?

    <p>It maintains the active state of CaMKII after activation</p> Signup and view all the answers

    What does the term 'occlusion' refer to in the context of the interaction between CaMKII-induced potentiation and LTP induction?

    <p>Inability to induce LTP due to prior CaMKII activation</p> Signup and view all the answers

    What is the consequence of a successful autophosphorylation at Thr286 for CaMKII?

    <p>It enables the enzyme to remain active for prolonged periods</p> Signup and view all the answers

    What effect does the activity-dependent binding of CaMKII to NR2B have on spine size?

    <p>It leads to re-structuring of F-actin, influencing spine size.</p> Signup and view all the answers

    What does the translocation of CaMKII to spines indicate following stimulation?

    <p>An increase in spine volume and potential synaptic strengthening.</p> Signup and view all the answers

    How does increased CaMKII expression affect silent retinotectal synapses during development?

    <p>It converts silent synapses to functional ones, similar to LTP induction.</p> Signup and view all the answers

    What is the primary structural role of βCaMKII in synaptic function?

    <p>It stabilizes F-actin, influencing synaptic stability.</p> Signup and view all the answers

    What is indicated by transient activation of CaMKII after local glutamate uncaging?

    <p>It reflects a synapse-specific increase in CaMKII activity.</p> Signup and view all the answers

    What role does the interaction between CaMKII and F-actin play in synaptic plasticity?

    <p>It facilitates the modulation of synaptic strength through spine enlargement.</p> Signup and view all the answers

    Which condition primarily characterizes retinotectal synapses during early development?

    <p>Predominance of silent synapses with low CaMKII levels.</p> Signup and view all the answers

    What is the significance of the synapse-specificity of CaMKII activation during synaptic processes?

    <p>It enables strengthening of only specific synapses that are activated.</p> Signup and view all the answers

    How does CaMKII's role in spine volume changes relate to learning and memory?

    <p>Persistent spine volume increase is linked to long-term memory formation.</p> Signup and view all the answers

    What mechanistic outcome is primarily associated with the transient activation of CaMKII upon synaptic stimulation?

    <p>A sustained increase in synaptic traction and strength.</p> Signup and view all the answers

    Study Notes

    Molecular Basis of Synaptic Plasticity II

    • CamKII:

      • Structure and functions
      • Mechanisms
      • Contribution to learning and memory

    • CREB:

      • LTP and synaptic capture
      • Excitability

    • IEGs:

      • Definition
      • Engrams and LTP
      • Arc and a novel mode of transmission

    • BDNF:

      • Structure and functions
      • Mechanisms
      • Contribution to learning and memory
      • Role in LTP
      • Role in spatial learning

    • CaMKII Activation States:

      • Brief activation
      • Short-term persistent activation
      • Long-term persistent activation

    • CaMKII and LTP:

      • LTP drives CaMKII persistent activity
      • LTP requires CaMKII persistent activity
      • CaMKII and LTP enhance synaptic transmission through the same mechanism

    • Mechanisms to Impact Transmission:

      • Association with NMDA receptors
      • Phosphorylation of AMPA receptors
      • Regulation of trafficking of AMPARs
      • Regulation of spine size

    • CamKII in vivo: Synaptic Maturation

      • Synaptic specificity and activation

    • CamKII in vivo: Learning and Memory

      • Deficient Hippocampal Long-Term Potentiation in α-Calcium-Calmodulin Kinase II Mutant Mice
      • Impaired Spatial Learning

    • CREB Inhibition:

      • CREB inhibition leads to long-term, but not short-term memory deficits
      • Increased CREB activity leads to increased expression of CREB-dependent genes

    • CREB: Phosphorylation:

      • CREB phosphorylation following fear training
      • LA neurons with increased CREB are more likely to be recruited into the memory trace

    • Ablation of LA Neurons:

      • Ablation of LA neurons overexpressing CREB blocks memory expression

    • CREB Overexpressing Neurons:

      • CREB overexpression increases intrinsic excitability
      • Increasing intrinsic excitability mimics CREB-mediated potentiation of memory

    • Immediate Early Genes (IEGs):

      • Rapid and transient induction by pre-existing transcription factors
      • Relatively short half-life
      • Arc, c-fos, Homer1a, zif268
      • Pattern of activity that triggers LTP leads to IEG expression

    • Engrams and the Locus of Memory:

      • Engrams and the concept of memory location
      • Reactivation of IEG-expressing neurons triggers memory recall

    • How do IEGs contribute to LTP?:

      • IEGs role in long-term plasticity
      • Impact on structural plasticity in the hippocampus following seizures
      • Arc mRNA moves to activated dendritic domains following stimulation

    • Arc Regulation of AMPAR Trafficking

      • Arc regulates AMPAR trafficking, showing increased steady state surface levels

    • Transfer of Arc mRNA:

      • Arc mRNA moves between neurons, using virus-like capsids

    • BDNF:

      • BDNF induces the synthesis of PKMC
      • BDNF is necessary for spatial learning
      • BDNF is involved in long-term potentiation
      • BDNF plays a role in neuronal development, survival, repair and plasticity

    • LTP Maintenance:

      • PKMζ is involved in LTP maintenance.

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    Description

    Test your knowledge on the role and structure of CaMKII in the brain. This quiz covers its isoforms, subunit combinations, and interactions with anchoring proteins. Dive into the intricate details of this vital enzyme's function and composition.

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