Final answer:
After a ligand binds to a tyrosine kinase receptor, the receptor dimerizes and undergoes autophosphorylation of tyrosine residues on its intracellular domain, which activates the receptor and stimulates a downstream cellular response.
Step-by-step explanation:
Autophosphorylation of Intrinsic Tyrosine Kinase Receptors
Immediately after a ligand binds to an intrinsic tyrosine kinase receptor, several key events occur that lead to the activation of the receptor and the initiation of a cellular response. One of the first events is the dimerization of the receptor, which means that two receptor molecules come together to form a dimer. Following this, autophosphorylation of tyrosine residues occurs on the intracellular domain of the receptors. This phosphorylation event is critical as it activates the tyrosine kinase activity of the receptor, leading to further downstream signaling events that result in a cellular response such as the entry of glucose into cells or the activation of DNA transcription. The phosphorylated tyrosine residues also create docking sites for other signaling proteins which propagate the signal within the cell. Eventually, the signal is terminated when a phosphatase enzyme removes the phosphate groups from the tyrosine residues, inactivating the receptor and allowing for the possibility of another signal transduction cycle upon binding of a new ligand.
It should be noted that although the ligand is internalized in some cases, such as with insulin, this is not the immediate consequence. The receptor does not become inactivated nor dissociate from its ligand immediately upon ligand binding. Therefore, the correct answer to the question is C) Autophosphorylation of tyrosine residues.