How does the phosphorylation of IRS 1 contribute to insulin signaling, and what is its significance?

Phosphorylation of IRS 1 inhibits downstream signaling pathways, reducing cell growth.

Phosphorylation of IRS 1 has no significant role in insulin signaling.

Phosphorylation of IRS 1 activates downstream signaling pathways, crucial for cell growth and metabolism.

Phosphorylation of IRS 1 leads to its degradation, terminating the signal.