Anti-SMAD3 (phospho-S423) Antibody

The SMAD3 protein undergoes activating phosphorylation at serine 423 downstream of TGF-β receptor stimulation, and this rabbit polyclonal reagent from Antibodies.com detects that phospho-epitope by Western blot. Supplied unconjugated at 1 mg/ml in phosphate buffered saline with 15 mM sodium azide (approx. pH 7.2), the antibody reacts with human, mouse, and rat samples and is applied to lysates from cells treated with TGF-β ligands or pathway inhibitors to monitor canonical SMAD activation status.

Phosphorylation at S423 marks the receptor-activated SMAD3 complex that translocates to the nucleus and drives transcription of target genes involved in epithelial-mesenchymal transition, extracellular matrix deposition, and tumor cell invasion. Researchers in fibrosis, oncology, and developmental biology use this reagent to distinguish active signaling from basal SMAD3 expression. The 100 µl pack size supports multiple immunoblotting experiments alongside loading controls, and aliquoted stocks should be stored frozen to preserve phospho-epitope recognition across repeated freeze-thaw cycles.