Second Messengers

GPCR Activation

Binding of a ligand to a GPCR causes a conformational change, leading to G protein activation and subsequent activation of second messengers.

cAMP Signaling

G proteins activate adenylyl cyclase to produce cAMP, which activates PKA to phosphorylate target proteins for cellular responses.

PKA Regulation

Inactive PKA has regulatory subunits that bind cAMP, leading to dissociation and activation of catalytic subunits for phosphorylation.

Calcium Ion Signaling

Ca++ acts as a key intracellular signaling mediator with various functions depending on its concentration, influencing processes like exocytosis, muscle contraction, and gene transcription.

Calcium Signaling Toolkit

Genes encode components like channels, pumps, buffers, and sensors that regulate Ca++ levels, affecting cellular responses and adaptation to stimuli.

Calmodulin

A major Ca++ sensor in cells, calmodulin binds Ca++ to activate intracellular signaling pathways by interacting with various proteins and serving as a regulatory subunit.