Anti-MYL9 (phospho-S19) Antibody

Raised in rabbit, this unconjugated polyclonal antibody from Antibodies.com selectively recognizes the phosphorylated form of myosin light chain 9 (MYL9) at serine 19, a regulatory switch that governs actomyosin contractility in smooth muscle and non-muscle cells. It is validated for Western blot on human, mouse, and rat samples and is supplied as a 100 µL liquid stock at 1 mg/ml in phosphate buffered saline (PBS) with 0.05% sodium azide at approximately pH 7.2.

MYL9 (also called MLC-2 or MRLC1) is phosphorylated at Ser19 by myosin light chain kinase (MLCK), and this modification drives the calcium-dependent contractile response in vascular and visceral smooth muscle as well as cytokinesis, cell migration, and platelet retraction. Researchers therefore use the reagent to study vascular tone, airway hyperresponsiveness, gastrointestinal motility, cardiac and skeletal muscle physiology, fibrosis, cytoskeletal remodeling, megakaryocyte maturation, and tumor cell motility. Pairing the phospho-specific reagent with a matched pan-MYL9 antibody is a standard way to confirm that band shifts in immunoblots reflect kinase-driven phosphorylation rather than loading variation.

The polyclonal mixture binds multiple epitopes surrounding phospho-S19, which improves signal robustness but makes the reagent less suitable for strictly clonotype-critical applications such as immunohistochemistry on fixed sections or flow cytometry. Refrigerated handling is recommended; for long-term storage, aliquot the antibody and freeze to avoid repeated freeze-thaw cycles. Sodium azide is included as a preservative and the buffer formulation is compatible with standard immunoblotting on PVDF or nitrocellulose membranes with chemiluminescent detection. For research use only.