Anti-HER2 (Ab-1221 / 1222) Antibody

This rabbit polyclonal reagent from Antibodies.com was raised against HER2 (also known as ERBB2 or Neu) phosphorylated on tyrosine residues 1221 and 1222, two adjacent autophosphorylation sites located in the C-terminal regulatory tail of the receptor. Phosphorylation at Y1221/Y1222 reflects ligand-independent receptor activation and couples to downstream RAS-MAPK and PI3K-AKT signalling, so the antibody is used to monitor HER2 activity rather than total receptor expression in fixed or lysed samples.

The antibody is supplied as 100 µL of unconjugated antiserum and is validated for Western blot, immunohistochemistry, and immunofluorescence on human tissue. The expected band size in Western blot is approximately 185 kDa, with the phospho-specific signal abolished by lambda phosphatase treatment or competition with the cognate phosphopeptide. Common uses include profiling HER2 activation in HER2-positive breast and gastric carcinoma models, investigating trastuzumab and lapatinib resistance mechanisms, and mapping receptor tyrosine kinase signalling in research use only studies.