Phosphorylation: Phosphorylation is the process of adding a phosphate group to a molecule, usually a protein. It can change the structure and function of the protein, regulating various cellular processes.
Signal Transduction: Signal transduction refers to the process by which an extracellular signal is transmitted into a response inside the cell. Protein kinases are key players in this process, relaying signals from outside to inside the cell.
Protein Phosphatases: Protein phosphatases are enzymes that remove phosphate groups from proteins. They work in opposition to protein kinases and help restore balance in phosphorylation levels within cells.