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Multiple Choice
What happens to the epidermal growth factor (EGF) receptor after its ligand binds to it?
A
It is immediately degraded by lysosomes.
B
It dimerizes and undergoes autophosphorylation.
C
It releases its ligand and becomes inactive.
D
It transports the ligand into the nucleus.
Verified step by step guidance
1
Understand the role of the epidermal growth factor (EGF) receptor: The EGF receptor is a transmembrane protein that plays a critical role in cell signaling. It binds to its ligand, epidermal growth factor, to initiate a cascade of intracellular events.
Recognize the process of receptor activation: When the EGF ligand binds to the receptor, it triggers conformational changes in the receptor, leading to dimerization (pairing of two receptor molecules). This is a key step in receptor activation.
Learn about autophosphorylation: After dimerization, the intracellular kinase domains of the EGF receptor phosphorylate specific tyrosine residues on each other. This process is called autophosphorylation and is essential for downstream signaling.
Clarify the fate of the receptor: The receptor does not immediately degrade, transport the ligand into the nucleus, or release the ligand to become inactive. Instead, autophosphorylation activates the receptor, allowing it to recruit signaling proteins and propagate the signal within the cell.
Understand the biological significance: The activation of the EGF receptor through dimerization and autophosphorylation is crucial for regulating processes such as cell growth, proliferation, and differentiation. Dysregulation of this pathway can lead to diseases like cancer.