title: A potential role for protein kinase C-epsilon in regulating megakaryocytic lineage commitment.
abstract: Multiple studies have shown that intracellular signal transduction by the protein kinase C (PKC) family participates in the initiation of megakaryocyte differentiation. In this study, multiple approaches addressed the functional contributions by specific PKC isozymes to megakaryocytic lineage commitment of two independent cell lines, K562 and human erythroleukemia (HEL). Pharmacologic profiles of induction and inhibition of megakaryocytic differentiation in both cell lines suggested a role for the calcium-independent novel PKCs, in particular PKC-epsilon. In transfection studies, the isolated variable domain of PKC-epsilon selectively blocked exogenous activation of the megakaryocyte-specific alpha IIb promoter. Constitutively active mutants of PKC-epsilon, but not of other PKC isozymes, cooperated with the transcription factor GATA-1 in the activation of the alpha IIb promoter. The functional cooperation between GATA-1 and PKC-epsilon displayed dependence on cellular milieu, as well as on the promoter context of GATA binding sites. In aggregate, the data suggest that PKC-epsilon specifically participates in megakaryocytic lineage commitment through functional cooperation with GATA-1 in the activation of megakaryocytic promoters.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
authors.forename: F K
authors.initials: FK
authors.lastname: Racke
authors.forename: D
authors.initials: D
authors.lastname: Wang
authors.forename: Z
authors.initials: Z
authors.lastname: Zaidi
authors.forename: J
authors.initials: J
authors.lastname: Kelley
authors.forename: J
authors.initials: J
authors.lastname: Visvader
authors.forename: J W
authors.initials: JW
authors.lastname: Soh
authors.forename: A N
authors.initials: AN
authors.lastname: Goldfarb
mesh_terms: D002227:Carbazoles / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D019070:Cell Lineage / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004224:Diterpenes / Q000494:pharmacology; D050981:Erythroid-Specific DNA-Binding Factors; D005455:Fluorescent Antibody Technique; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020014:K562 Cells; D008301:Maleimides / Q000494:pharmacology; D008533:Megakaryocytes / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D021381:Protein Transport / Q000187:drug effects; D020218:Response Elements / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D002227:Carbazoles; D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins; D004224:Diterpenes; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D007211:Indoles; D007527:Isoenzymes; D008301:Maleimides; D014157:Transcription Factors; C081021:Go 6976; C011875:ingenol dibenzoate; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; C070515:bisindolylmaleimide I