PTM

PTM most commonly stands for post-translational modification, a covalent alteration of a protein after it has been synthesized. PTMs diversify the proteome, rapidly modulating protein function and interactions without changes to the underlying genetic code. They are often reversible and regulated by cellular signals, enabling dynamic control of processes such as signaling, metabolism, and structural organization.

Common PTMs include phosphorylation, glycosylation, ubiquitination, acetylation, methylation, lipidation, and sumoylation, as well as regulated proteolytic cleavage. Phosphorylation, added by kinases, frequently alters enzyme activity or protein interactions. Glycosylation attaches carbohydrate groups and influences folding, stability, and cell recognition. Ubiquitination can mark proteins for degradation or alter signaling. Acetylation and methylation modify lysine or arginine residues, often regulating chromatin state or protein interactions. Lipidation promotes membrane association, while sumoylation affects localization and stability. Proteolytic processing can convert precursors into active forms.

Detection and study of PTMs rely on proteomics approaches, especially mass spectrometry. Enrichment strategies and high-resolution analysis identify specific modification sites, enabling mapping of dynamic changes across conditions, cell types, or developmental stages. PTMs are context-dependent, often changing in response to stimuli such as stress, growth factors, or energy status, and they can act combinatorially to regulate complex networks.

Biologically, PTMs regulate enzyme activity, localization, interactions, and stability, thereby shaping signaling pathways, gene expression, and cell fate. Aberrant PTM regulation is associated with diseases including cancer, neurodegeneration, and metabolic disorders. Therapeutic strategies increasingly target PTM enzymes, such as kinase inhibitors, phosphatase modulators, ubiquitin ligases, or deubiquitinases, underscoring the clinical relevance of PTMs.

In contexts outside biology, PTM can denote various organizations, technologies, or project names depending on usage. When encountered, interpretation relies on accompanying context or definitions.