IRS1 and Insulin resistance: In addition, Aβ was observed to promote insulin resistance through promoting the serine phosphorylation of insulin receptor substrate-1 (IRS-1) [32], resulting in the reduction of phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) expression and enhanced glycogen synthase kinase-3 beta (GSK3β) activity [33].