phosphorylationactivated

Phosphorylation is a common post-translational modification in which a phosphate group is covalently attached to an organic molecule, most often proteins. In eukaryotes, phosphorylation typically occurs on serine, threonine, or tyrosine residues, modulated by enzymes called protein kinases that transfer a phosphate from ATP to the substrate. The reverse reaction is catalyzed by phosphatases that remove phosphate groups. This reversible modification changes the chemical properties of the target, often inducing conformational changes, altering activity, localization, stability, or interactions with other proteins.

Phosphorylation participates in cellular signaling networks, enabling rapid responses to stimuli. Phosphorylation cascades, such as the MAPK and PI3K–AKT pathways, transmit signals through sequential kinase activations. It can regulate enzymatic activity directly or create docking sites for phospho-dependent domains (such as SH2 or 14-3-3 proteins).

ATP is the common phosphate donor in cells, though other donors exist in specific systems. Phosphorylation is dynamic and tightly controlled; aberrant phosphorylation is linked to diseases, including cancer, diabetes, and neurodegenerative disorders. Therapeutic strategies include kinase inhibitors and phosphatase modulators.

Methods to study phosphorylation include mass spectrometry-based phosphoproteomics and antibody-based detection of phosphorylated residues.

Phosphorylation is a versatile and essential mechanism for regulating cellular processes.