酶联受体

Some receptors also act as enzymes, molecules that accelerate chemical reactions.

The receptor tyrosine kinases or RTKs are one family of enzyme-linked receptors. When a signaling molecule, the ligand, binds, two membrane-bound RTKs dimerize or aggregate.

This process activates the tyrosine kinase activity in the cytoplasmic tail of the receptors. Each RTK in the dimer transfers a phosphate group from ATP to tyrosines on the other RTK in a process called phosphorylation.

Once the tyrosines have phosphates attached, the dimer becomes activated. Now, different relay proteins can bind to specific phosphorylated tyrosines, becoming activated and initiating their own signal transduction pathways that lead to diverse cellular responses.