What is the significance of IRS 1 phosphorylation in insulin signaling?

• A. IRS 1 phosphorylation has no significant role in insulin signaling.
• B. IRS 1 phosphorylation is crucial for activating downstream signaling pathways involved in cell growth.
• C. IRS 1 phosphorylation inhibits downstream signaling pathways, reducing cell growth.
• D. IRS 1 phosphorylation leads to its degradation, terminating the signal.

Answer: (B)