In order to impact cell differentiation and proliferation, the insulin receptor substrate 1 must be phosphorylated on a residue and directly bind to .

on a tyrosine residue

bind to insulin

Explanation:

The insulin receptor substrate-1 (IRS1) is a signaling protein that can be phosphorylated on multiple tyrosine and serine/threonine residues. IRS1 contains several conserved domains including a pleckstrin (PH) domain and a PTB domain involved in protein phosphorylation and ligand binding. In the first place, IRS1 is phosphorylated on a tyrosine residue, and then IRS1 binds to insulin or the insulin-like growth factor-1 (IGF-1), thereby activating transduction pathways such as, for example, MAPK/ERK. Moreover, RS1 is also phosphorylated on serine residues, thereby triggering opposite effects in insulin-associated signaling.

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