Phospho-ERK1/2 (Thr202/Tyr204)/(Thr185/Tyr187) antibodies are essential tools for studying the activation status of extracellular signal-regulated kinases 1 and 2 (ERK1/2), key components of the mitogen-activated protein kinase (MAPK) signaling pathway. ERK1/2 are serine/threonine kinases that regulate diverse cellular processes, including proliferation, differentiation, survival, and apoptosis. Their activation requires dual phosphorylation at specific threonine and tyrosine residues: Thr202/Tyr204 in ERK2 (also called p42 MAPK) and Thr185/Tyr187 in ERK1 (p44 MAPK). This phosphorylation is mediated by upstream MAPK/ERK kinases (MEK1/2) in response to growth factors, cytokines, or cellular stress.
Phospho-specific antibodies targeting these residues enable researchers to detect activated ERK1/2 in cells or tissues, providing insights into pathway activity under experimental or pathological conditions. They are widely used in techniques like Western blotting, immunofluorescence, and flow cytometry. Such antibodies are critical in cancer research, as hyperactivation of ERK1/2 is linked to tumor progression and drug resistance. Validation often includes testing with stimulated cells (e.g., treated with EGF or PMA) and verifying loss of signal upon MEK inhibition. Cross-reactivity with other phosphorylated MAPKs (e.g., JNK, p38) is uncommon in well-validated antibodies. Proper controls, such as total ERK1/2 detection, are recommended to distinguish activation state from protein expression levels. These antibodies also serve as biomarkers in drug development, particularly for therapies targeting the MAPK pathway.