This phosphorylated TAT-HSP20 was physiologically active in intact smooth muscles in that it inhibited 5-hydroxytryptamine-induced contractions by 57%+/-4.5.     ///    Immunoblot and HPLC-ESI-MS/MS analysis of the purified TAT-HSP20 demonstrated that it was phosphorylated at serine 40 (equivalent to serine 16 in wild-type human HSP20).     ///    "In this study, we co-expressed in Escherichia coli the cDNAs encoding the catalytic subunit of protein kinase G and a TAT-HSP20 fusion protein composed of the TAT PTD (-YGRKKRRQRRR-) fused to the N-terminus of human HSP20. "