What are the major types of post-translational modifications?

Post-translational modifications refer to the alterations that occur in a protein after it has been synthesized. These modifications play a crucial role in determining the structure, function, and localization of a protein, thereby influencing various cellular processes. Some major types of post-translational modifications include:

• Phosphorylation: Addition of a phosphate group to proteins, often carried out by kinases, which can regulate enzyme activity, protein-protein interactions, and cellular signaling pathways.
• Glycosylation: Attachment of sugar molecules to proteins, affecting protein folding, stability, and cell-cell recognition.
• Acetylation: Addition of an acetyl group to proteins, commonly found in histones and affecting gene expression and chromatin structure.
• Methylation: Addition of methyl groups to proteins, influencing protein-protein interactions, enzyme activity, and DNA repair processes.
• Proteolysis: Cleavage of proteins by proteases, regulating protein activation, degradation, and signaling cascades.
• Ubiquitination: Attachment of ubiquitin molecules to proteins, marking them for degradation by the proteasome or influencing protein localization and function.

These post-translational modifications can alter the structural conformation, activity, stability, and interactions of proteins, ultimately impacting various cellular processes and contributing to the complexity and diversity of the proteome.