Post-translational modification
Covalent protein changes after synthesis, diversifying function and regulation.
Post-translational modifications (PTMs) are the covalent processes of changing proteins following their synthesis and release from ribosomes. They are reversible editing events used in post-translational regulation, the control of levels of active protein, and enable protein function to be diversified beyond the dictates of transcription.
- field
- Biochemistry, Molecular Biology
- known_for
- Covalent modification of proteins after translation, expanding protein function and regulating activity
- occurrence
- Eukaryotic and prokaryotic cells
- common_type
- Phosphorylation
Lore & Background
Post-translational modifications (PTMs) involve enzymes or occur spontaneously. Proteins are created by ribosomes, which translate mRNA into polypeptide chains, which may then change to form the mature protein product, released from the ribosome. PTMs are important components in cell signaling, as when prohormones are converted to hormones. They can occur on amino acid side chains or at the protein's C- or N-termini, expanding the chemical set of the 22 amino acids by changing an existing functional group or adding a new one such as phosphate. Phosphorylation is highly effective for controlling enzyme activity and is the most common change after translation. Many eukaryotic and prokaryotic proteins also have carbohydrate molecules attached via glycosylation, which can promote protein folding and improve stability as well as serving regulatory functions. Attachment of lipid molecules, known as lipidation, often targets a protein or part of a protein attached to the cell membrane.
Reader's Guide
Post-translational modifications are fundamental to cellular regulation, enabling rapid, reversible control of protein activity without altering gene expression. They expand the functional diversity of proteins far beyond what is encoded in the genome, influencing processes such as signal transduction, protein stability, localization, and interactions. PTMs like phosphorylation, glycosylation, and lipidation are critical for normal cell function, and dysregulation of PTM pathways is implicated in diseases including cancer and neurodegenerative disorders. The study of PTMs is essential for understanding cellular biology and for developing therapeutic strategies. Detection techniques such as mass spectrometry and Western blotting allow researchers to identify and characterize these modifications, providing insights into their roles in health and disease.
Did You Know?
- Phosphorylation is the most common post-translational modification and is highly effective for controlling enzyme activity.
- PTMs can occur on amino acid side chains or at the protein's C- or N-termini.
- Some PTMs, such as carbonylation, are consequences of oxidative stress and can target proteins for degradation.
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