CREB

Definition

CREB, or cAMP response element-binding protein, is a cellular transcription factor that plays a critical role in regulating gene expression in response to various signals, particularly those involving cyclic AMP (cAMP). It acts as a mediator of cellular responses to hormones and other signaling molecules, influencing processes such as metabolism, growth, and memory formation.

5 Must Know Facts For Your Next Test

1. CREB is activated through phosphorylation by various kinases, including protein kinase A (PKA), which is activated by cAMP.
2. Once activated, CREB binds to cAMP response elements (CRE) in the promoter regions of target genes, facilitating their transcription.
3. CREB is involved in numerous cellular processes, including neuronal plasticity and long-term memory formation in the brain.
4. Disruptions in CREB function have been linked to various diseases, including depression and certain cancers.
5. The activity of CREB can be modulated by other proteins and signaling pathways, demonstrating its role in a complex network of cellular responses.

Review Questions

• How does phosphorylation influence the function of CREB and its role in gene expression?
  • Phosphorylation is essential for the activation of CREB. When CREB is phosphorylated by kinases like protein kinase A (PKA), it undergoes a conformational change that enables it to bind to specific DNA sequences known as cAMP response elements (CRE). This binding allows CREB to initiate the transcription of target genes involved in various cellular processes, such as metabolism and memory formation. Without phosphorylation, CREB remains inactive and unable to regulate gene expression.
• Discuss the relationship between CREB and cAMP signaling pathways in the context of hormone action.
  • CREB functions as a key mediator in cAMP signaling pathways activated by hormones like adrenaline. When these hormones bind to their receptors on the cell surface, they stimulate the production of cAMP. Elevated levels of cAMP activate PKA, which then phosphorylates CREB. This phosphorylation allows CREB to promote the transcription of genes responsive to these hormonal signals, thereby linking external hormonal signals to internal cellular responses. This illustrates how CREB integrates hormonal actions into gene regulation.
• Evaluate the implications of altered CREB activity in human diseases and potential therapeutic approaches.
  • Alterations in CREB activity can significantly impact various physiological processes and are implicated in diseases such as depression and cancer. For example, reduced CREB function may impair memory formation and contribute to cognitive disorders. Understanding these connections opens up potential therapeutic avenues, such as developing drugs that can enhance or inhibit CREB activity. By targeting the signaling pathways that regulate CREB, new treatments could be designed to restore normal function in conditions where CREB is dysregulated.

Related terms

Transcription Factor: A protein that binds to specific DNA sequences, controlling the transcription of genetic information from DNA to messenger RNA.

cAMP:

Cyclic adenosine monophosphate, a secondary messenger that transmits signals from hormones and neurotransmitters to elicit cellular responses.

Phosphorylation:

The addition of a phosphate group to a molecule, often used in the regulation of proteins, including the activation of CREB.