Human Smtnl1-phospho-S301 ELISA Kit (HUFI06424)

Phosphorylation-state ELISA from Assay Genie that quantifies site-specific phosphorylation of smoothelin-like protein 1 (SMTNL1) at Ser-301, the only residue targeted by cAMP- and cGMP-dependent protein kinases (PKA and PKG) in vivo. SMTNL1, also known as CHASM (calponin homology-associated smooth muscle protein), is a 53 kDa member of the smoothelin family that is expressed in vascular smooth muscle and in type 2a skeletal muscle fibers. In its dephosphorylated state the protein suppresses myosin light chain phosphatase activity toward myosin, blocking dephosphorylation of the contractile apparatus; phosphorylation at Ser-301 lifts that inhibition, providing a direct biochemical link to cGMP- and cAMP-mediated vasorelaxation and to the exercise-adapted vascular phenotype reported in smtnl1 knockout mouse studies. Investigators tracking smooth muscle phenotype switching, myofibroblast differentiation, or cytoskeletal remodeling in vascular and striated muscle contexts can profile activation-state dynamics of SMTNL1 in human serum-type or plasma-type specimens. The kit is supplied as a complete set of materials for 96 individual determinations and includes a dismountable 8x12 strip microplate, a lyophilized phospho-Ser-301 standard, detection reagent vials, wash buffer, substrate, and stop solution; all components should be refrigerated at 4 degrees C to preserve antibody binding activity and standard integrity through the stated shelf life.