S100A13 is not expressed on the surface of coronary artery smooth muscle cells (CASMCs), but oxidative stress induced surface expression of S100A13.

A) Binding of recombinant S100A13 on the surface of CASMCs were examined by flow cytometory. CASMCs were preincubated with vehicle only (1st panel) or recombinant S100A13 in the presence of vehicle (2^nd panel), 0.1 mM CaCl₂ (3^rd panel), 1 mM EDTA (4^th panel), or 0.1 mM CaCl₂ + 1 mM EDTA (5^th panel). After excess of the recombinant protein was removed by centrifugation, cells were incubated with control mouse IgG (filled) or anti-S100A13 antibody (line), followed by Alexa Flour 488-conjugated anti-mouse IgG. B) Surface expression of endogenous S100A13 was analyzed by flow cytometry. CASMCs pretreated with indicated concentrations of H₂O₂ were incubated with control mouse IgG (filled) or anti-S100A13 antibody (line), followed by Alexa Flour 488-conjugated anti-mouse IgG.