IRS1 and Alzheimer disease: Of the three serine residues on IRS1, increased levels of phosphorylation at mSer307 (hSer312) and mSer612 (hSer616) are observed in AD hippocampus and cerebral cortex 81, 82, 83, whereas the phosphorylation level of mSer632/635 (hSer 636/639), which is also elevated in the brain from patients with AD or AD‐transgenic model mice, is comparable in the hippocampus between groups (Fig. 5A,E).