Final answer:
RTK trans-autophosphorylation is initiated when a signaling molecule binds to the extracellular domain of the receptor, causing dimerization. This triggers the autophosphorylation of tyrosine residues, which play a crucial role in downstream cellular responses.
Step-by-step explanation:
The purpose of RTK (Receptor Tyrosine Kinase) trans-autophosphorylation is to initiate a downstream cellular response. When a signaling molecule binds to the extracellular domain of the RTK, it causes the receptor to dimerize. This dimerization triggers the autophosphorylation of tyrosine residues on the intracellular domain of the receptor.
The phosphorylated tyrosine residues then serve as docking sites for downstream signaling molecules, leading to various cellular responses.