Fig 2: PKD1-mediated KAT7 phosphorylation increases KAT7 protein expression.a PKD1 overexpression increases KAT7 protein expression. HEK293T, H1299 and HeLa cells were transfected with either empty vector or HA-PKD1-CA. The total cell lysates were subjected to western blotting for the indicated proteins (upper panel). The total RNAs were extracted and the mRNA levels of KAT7 were measured by real-time PCR (lower panel). b PKD1 knockdown decreases KAT7 protein expression. The control siRNA or PKD1 siRNAs were transfected into HEK293T, H1299 and HeLa cells. The protein levels and mRNA levels of KAT7 were measured as above. c, d PKD1 regulates KAT7 expression in a dose-dependent manner. Different doses of HA-PKD1-CA or PKD1 siRNAs were transfected into HEK293T cells. The indicated proteins were measured by Western blotting. e PKD1 kinase activity is important for promoting KAT7 protein expression. The empty vector, HA-PKD1-CA or HA-PKD1-KD plasmids were transfected into HEK293T and HeLa cells, respectively. The indicated proteins were measured by Western blotting. f HEK293T cells were treated with or without Gö6976, then the indicated proteins were measured by Western blotting. g HEK293T cells were treated with or without PMA, then the indicated proteins were measured by Western blotting. h FLAG-KAT7 or KAT7-T97/331A mutant were transfected with or without HA-PKD1-CA into HEK293T cells, GFP plasmid also was transfected into all samples. The indicated proteins were measured by Western blotting. GFP protein levels are shown as equal transfection efficiency.

Fig 3: Divergent pathways promoted by PGE 2 synergistically activate the transcription factor MEF2Schematic representation of the PGE2 triggered signal transduction pathways converging on HDAC5 and subsequently MEF2. PGE2 activates MEF2 through EP3 receptor and the βγ subunit of Gi/o proteins. One pathway implicates activation of PKD and concomitant phosphorylation of HDAC5. The phosphorylated HDAC5 is exported from the nucleus, which results in de‐repression of MEF2 and activation of the embryonic gene programs. In addition, hand in hand activation of Tiam1, Rac1, and PAK2 kinase occurs, which pathway also contributes to the nuclear export of HDAC5 and is responsible for synergistic activation of MEF2.

Fig 4: PGE 2 triggers phosphorylation of PKD in adult mouse ventricular myocytesAdult mouse ventricular myocytes were serum starved for 4 h and treated with 1 μM PGE2 or 100 nM ET1 for 4 h. Phosphorylation of PKD was assessed by immunoblot. Representative images are shown.Source data are available online for this figure.

Fig 5: PKD1-mediated phosphorylation of KAT7 at T97/331 promotes pre-RC formation and cell proliferation.a Phosphorylation of KAT7 by PKD1 is important for pre-RC formation. HeLa cells transfected with or without HA-PKD1-CA were subjected to western blot for the indicated proteins. b HeLa cells transfected with PKD1 siRNA or control siRNA were subjected to western blot for the indicated proteins. c HeLa cells transfected with vector, KAT7-WT and KAT7-T97/331A mutant were subjected to western blot for the indicated proteins. d HeLa cells transfected with KAT7 3’-UTR siRNA or control siRNA were immunoblotted with KAT7 antibody to examine KAT7 knockdown efficiency. e HeLa cells were transfected with KAT7 3’-UTR siRNA for 24 h, then re-introduced with vector, WT-KAT7 and KAT7-T97/331A mutant for another 48 h. Cell lysates were subjected to western blot for the indicated proteins. f HeLa cells transfected with or without HA-PKD1-CA were lysed and separated to cytoplasmic, soluble nucleoplasmic and chromatin-enriched fractions, respectively. Then chromatin-enriched fractions were subjected to western blot analysis for the indicated proteins. g HeLa cells transfected with vector, WT-KAT7 and KAT7-T97/331A mutant were lysed and separated to cytoplasmic, soluble nucleoplasmic and chromatin-enriched fractions, respectively. Then chromatin-enriched fractions were subjected to western blot analysis for the indicated proteins. h HeLa cells were stably infected with PHBLV, KAT7-WT and KAT7-T97/331 A lentiviruses, respectively, and then cell growth curves were determined by CCK-8/WST-8 assay for the indicated time. i HeLa cells infected as h were cultured for 10–14 days, then colony formation assay was performed. j Hela cells were infected as h, and then EdU incorporation assay was conducted.