Figure 3. HDAC4 is a substrate of PKA.

A, muscle fibres were infected with wt HDAC4-GFP or HDAC4 (S265/266A)-GFP. After 2 days in culture, muscle cultures were treated with Db cAMP. Total cell lysates were first incubated with anti-phospho-PKA substrate antibodies for immunoprecipitation then immunobloted with anti-GFP antibodies. The band is consistent with the molecular weight of HDAC4-GFP. The experiment was repeated three times, each time using two mice. B, alignment of amino acid sequences surrounding HDAC4 serines 265 and 266, showing the PKA phosphorylation motif is conserved in human and mouse HDAC4 and 5. C, cartoon showing the phosphorylation sites of CaMKII and PKA in HDAC4.