Creb Cycle: Matching Steps, Molecules, Events, and Regulatory Elements

Questions and Answers

Match the following steps in the Creb cycle with their descriptions:

Creb phosphorylation = Binding of PKA to the regulatory subunit of PKA
Activated PKA phosphorylation = Creb protein is phosphorylated
Creb binds to CRE = Activated Creb binds to the cAMP response element (CRE)
Transcriptional activation = Gene transcription is enhanced

Match the following molecules with their roles in the Creb cycle:

cAMP = Secondary messenger that activates PKA PKA = Kinase that phosphorylates Creb Creb = Transcription factor that binds to CRE ATP = Energy source for phosphorylation reactions

Match the following events with their triggers in the Creb cycle:

Increase in cAMP levels = Binding of hormone to the G-protein coupled receptor Phosphorylation of Creb = Activation of PKA Transcription of target genes = Binding of Creb to CRE Dissociation of the inhibitory subunit = Activation of PKA

Match the following regulatory elements with their functions in the Creb cycle:

<p>CRE = Binding site for phosphorylated Creb G-protein coupled receptor = Receptor that binds to hormone and activates adenylate cyclase Inhibitory subunit = Subunit that inhibits PKA in the absence of cAMP CAAT box = Binding site for other transcription factors</p> Signup and view all the answers

Match the following outcomes with their effects on the Creb cycle:

<p>Protein kinase A (PKA) inhibition = Decreased phosphorylation of Creb Overexpression of Creb = Increased transcription of target genes Mutations in the CRE = Reduced binding of phosphorylated Creb cAMP accumulation = Increased phosphorylation of Creb</p> Signup and view all the answers

Study Notes

Creb Cycle: Matching Steps, Molecules, Events, Regulatory Elements, and Outcomes

Steps in the Creb Cycle

Steps involve the activation and deactivation of Creb (CAMP response element-binding protein)
Phosphorylation of Creb by Protein Kinase A (PKA) is a crucial step
De-phosphorylation of Creb by Phosphatases reverses the activation

Molecules in the Creb Cycle

Creb (CAMP response element-binding protein): a transcription factor that regulates gene expression
Protein Kinase A (PKA): phosphorylates Creb, activating it
Phosphatases: de-phosphorylate Creb, deactivating it
CAMP (Cyclic Adenosine Monophosphate): a second messenger that activates PKA

Events in the Creb Cycle

Phosphorylation of Creb: triggered by increased CAMP levels
Activation of gene transcription: triggered by phosphorylated Creb
De-phosphorylation of Creb: triggered by decreased PKA activity

Regulatory Elements in the Creb Cycle

Creb binding site: a DNA sequence that Creb binds to, regulating gene transcription
CAMP Response Element (CRE): a specific DNA sequence that Creb binds to
CBP (Crebbp): a co-activator that enhances Creb-mediated transcription

Outcomes of the Creb Cycle

Regulation of gene expression: phosphorylated Creb activates gene transcription
Cellular responses: regulated by Creb-mediated gene transcription, e.g., cell growth and differentiation

Description

Test your knowledge of the Creb cycle by matching its key components, including steps, molecules, events, and regulatory elements. Understand the triggers, functions, and effects of each element in the cycle.