<prompt> Answer this question truthfullyWhat are cAMP response element binding CREB proteins, and what is their role in cellular response to cAMP?  <response>: <reason> cAMP response element binding CREB proteins are a type of specific transcription factors that can bind to cAMP response elements CREs in DNA. They play a key role in cellular response to cAMP, a secondary messenger molecule that is involved in many physiological processes. When CREB proteins bind to CREs, they can activate or repress the transcription of target genes, leading to a variety of cellular responses to cAMP. 