Tyrosine kinase receptors are a type of protein found on the surface of cells that play a crucial role in cell communication. When specific molecules, known as ligands, bind to these receptors, they trigger a series of chemical reactions inside the cell. This process helps regulate various cellular functions, including growth, differentiation, and metabolism. These receptors are characterized by their ability to add phosphate groups to the amino acid tyrosine in proteins, a process called phosphorylation. This modification activates signaling pathways that can influence cell behavior, making tyrosine kinase receptors important in processes like development and immune responses.