Fig 2: 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 3: PGE 2‐induced Rac1 activation does not involve PKD Serum‐starved NRVMs were treated with 3 μM BPKDi prior to stimulation. After treatment with 10 μM PGE2 for 2 min, Rac1 activation was determined by effector pull‐down assay. Representative image from three independent experiments.Source data are available online for this figure.

Fig 4: 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.

Fig 5: PKD1 interacts with KAT7 in vitro and in vivo.a KAT7 were pulled down by Flag-PKD1. Cellular extracts from HEK293T cells overexpressing FLAG-PKD1 were immunoprecipitated with anti-FLAG antibody and Protein G-Sepharose beads. After extensively washing the beads, immobilized proteins were eluted in SDS–PAGE sample buffer. The eluent was resolved by SDS–PAGE and silver stained. The protein bands were retrieved and analyzed by mass spectrometry. b–e PKD1 interacts with KAT7 in vivo. b HEK293T cells were co-transfected with HA-PKD1 and Flag-KAT7 plasmids. IP assay and subsequent western blotting were performed by using the indicated antibodies in the panel. c HEK293T cells were transfected with Flag-KAT7 and HeLa cells were transfected with Flag-PKD1, IP assay was carried out by using anti-FLAG antibody and followed by western blotting with anti-KAT7 or anti-PKD1 antibody, respectively. d, e Whole-cell lysates from HEK293T, HeLa, or H1299 cells were immunoprecipitated with anti-KAT7 or anti-PKD1 antibodies followed by immunoblotting with the indicated antibodies. f PKD1 interacts with KAT7 in vitro. GST pull-down assay were performed with bacterial expressed GST-KAT7 protein and HEK293T-expressed FLAG-PKD1. g The schematic representation of the key domains within KAT7 was depicted, and GST pull-down assay was performed by incubating GST-KAT7 or its various deletion mutants with HEK293T-expressed HA-PKD1.