> See also: > - [[Proteins]] # Protein Interactions Protein-protein interactions have many intra- and intercellular activities including: - Maintaining structure - Transducing signals - Regulating Gene Expression - ## Phosphorylation Phosphorylation occurs when a phosphate group is added to the protein which can lead to activation. Adding a phosphate group changes the charge of the protein, decreases the hydrophobicity, and allows for other molecules to recognize the phosphorylated protein. As the charge of the protein is changed, it can change interactions with other amino acids which can lead to other changes including changes in the conformation. ## Acetylation ## Nucleic Acid Binding > See also: > - [[Nucleic Acids]] Major vs Minor groove