Anti-pMyoDT115 antibody is specific for MyoD phosphorylated at T115 A, spots of phosphopeptide, but not dephosphopeptide, were clearly detected down to < 10 ng. B, Western blot of nuclear extracts from Hek-293 cells after transfection with pCMS-EGFP expressing EGFP only (sham), pCMS-EGFP-MyoDwt expressing wild type MyoD, pSP3-MyoD expressing MyoD with a S200A mutation, or pCMS-EGFP-MyoDA115 expressing MyoD with a T115A mutation. The blots were stained with anti-MyoD or anti-pMyoDT115. Loading was adjusted for differences in transfection efficiency by adjusting the load to yield equal signals with anti-MyoD.