Insulin binding to its receptor causes tyrosine phosphorylation at positions 1158, 1162, and 1163, facilitating IRS binding and subsequent tyrosine phosphorylation.

“tyrosine phosphorylation when insulin binds the receptor these three tyrosines the 1158 the 1162 and the 1163 become phosphorylated that opens the door that loop flips out and then irs wants to go into the pocket and undergo tyrosine phosphorylation to get the rest of the cascade going”