What is the significance of IRS 1 acting as an adapter protein in insulin signaling?

• A. IRS 1 facilitates the binding of PI3K to phosphorylated tyrosine residues, activating PI3K.
• B. IRS 1 inhibits the autophosphorylation of the insulin receptor, preventing signal transduction.
• C. IRS 1 degrades PIP3, terminating the signaling cascade.
• D. IRS 1 directly transports glucose into the cell, bypassing GLUT4.

Answer: (A)