cAMPsensitive

cAMPsensitive is a term used in molecular biology to describe a cellular component, typically a protein, that exhibits a change in its activity or function in response to variations in the intracellular concentration of cyclic adenosine monophosphate (cAMP). cAMP is a crucial second messenger involved in a wide array of cellular signaling pathways, mediating responses to hormones, neurotransmitters, and other extracellular stimuli. When these stimuli bind to their respective receptors on the cell surface, they can trigger the activation of adenylyl cyclase, an enzyme that synthesizes cAMP from adenosine triphosphate (ATP).

Proteins that are cAMPsensitive often possess a regulatory domain that can bind to cAMP. Upon binding, this interaction causes a conformational change in the protein, leading to its activation or inhibition. A prominent example of a cAMPsensitive protein is protein kinase A (PKA), also known as cAMP-dependent protein kinase. In its inactive state, PKA consists of two regulatory subunits and two catalytic subunits. cAMP binds to the regulatory subunits, causing them to dissociate from the catalytic subunits. This release activates the catalytic subunits, allowing them to phosphorylate target proteins, thereby modulating their activity and propagating the cellular signal. Other examples of cAMPsensitive proteins include ion channels, transcription factors, and guanine nucleotide exchange factors, all playing vital roles in cellular regulation. The sensitivity of these proteins to cAMP levels allows cells to finely tune their responses to external cues.