title: Functional role for protein kinase Cbeta as a regulator of stress-activated protein kinase activation and monocytic differentiation of myeloid leukemia cells.
abstract: Human myeloid leukemia cells respond to 12-O-tetradecanoylphorbol-13-acetate (TPA) and other activators of protein kinase C (PKC) with induction of monocytic differentiation. The present studies demonstrated that treatment of U-937 and HL-60 myeloid leukemia cells with TPA, phorbol-12,13-dibutyrate, or bryostatin 1 was associated with the induction of stress-activated protein kinase (SAPK). In contrast, TPA-resistant TUR and HL-525 cell variants deficient in PKCbeta failed to respond to activators of PKC with the induction of SAPK. A direct role for PKCbeta in TPA-induced SAPK activity in TUR and HL-525 cells that stably express PKCbeta was confirmed. We showed that TPA induced the association of PKCbeta with MEK kinase 1 (MEKK-1), an upstream effector of the SAPK/ERK kinase 1 (SEK1)-->SAPK cascade. The results also demonstrated that PKCbeta phosphorylated and activated MEKK-1 in vitro. The functional role of MEKK-1 in TPA-induced SAPK activity was further supported by the demonstration that the expression of a dominant negative MEKK-1 mutant abrogated this response. These findings indicate that PKCbeta activation is necessary for activation of the MEKK-1-->SEK1-->SAPK cascade in the TPA response of myeloid leukemia cells.
authors.affiliation: Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kaneki
authors.forename: S
authors.initials: S
authors.lastname: Kharbanda
authors.forename: P
authors.initials: P
authors.lastname: Pandey
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Takekawa
authors.forename: J R
authors.initials: JR
authors.lastname: Liou
authors.forename: R
authors.initials: R
authors.lastname: Stone
authors.forename: D
authors.initials: D
authors.lastname: Kufe
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002454:Cell Differentiation; D004789:Enzyme Activation; D018922:HL-60 Cells; D006367:HeLa Cells; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D048031:JNK Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; D020928:Mitogen-Activated Protein Kinases; D008934:Mitogens / Q000494:pharmacology; D009000:Monocytes / Q000166:cytology* / Q000187:drug effects; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D064546:Protein Kinase C beta; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D007527:Isoenzymes; D008934:Mitogens; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482576:MAP3K1 protein, human; D013755:Tetradecanoylphorbol Acetate