Intracellular signaling enzymes and pathways

Intracellular signaling enzymes and pathways represent a broad and complex category of molecular mechanisms that transmit external signals from the cell surface to internal effectors to elicit a biological response (NIH, 2022). These pathways are primarily mediated by enzymes such as protein kinases, phosphatases, and GTPases, which act as molecular switches through post-translational modifications like phosphorylation (StatPearls, 2023). By regulating essential processes including growth, differentiation, and survival, these signaling networks are critical for maintaining cellular homeostasis. Dysregulation of these pathways, such as the constitutive activation of the MAPK/ERK or PI3K/AKT/mTOR cascades, is a fundamental driver of oncogenesis and inflammatory diseases (Nature Reviews Drug Discovery, 2021). Consequently, specific enzymes within these pathways serve as major therapeutic targets for small molecule inhibitors and biological agents. While highly effective, targeting these pathways often presents challenges such as the emergence of compensatory resistance mechanisms and potential toxicity due to the essential roles these enzymes play in normal physiology.

Other names

Signal transduction pathwaysIntracellular signaling cascadesCell signaling moleculesIntracellular signaling network

Drugs targeting these pathways typically function as small molecule inhibitors that compete with ATP or substrates at the active site of enzymes, or act as allosteric modulators to inhibit or activate specific signaling nodes (StatPearls, 2023).