Extracellular signal-regulated kinase/90-KDA ribosomal S6 kinase/nuclear factor-kappa B pathway mediates phorbol 12-myristate 13-acetate-induced megakaryocytic differentiation of K562 cells.
Two signaling pathways, the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK)-dependent pathway and the nuclear factor-kappaB (NF-kappaB)-dependent pathway, have been known to mediate megakaryocytic differentiation of K562 cells induced by phorbol 12-myristate 13-acetate (PMA). In this study, we examined whether 90-kDa ribosomal S6 kinase (RSK), known as a substrate of ERK/MAPK and a signal-inducible IkappaBalpha kinase, would link two pathways during the differentiation. RSK1 was activated in a time- and dose-dependent manner during the PMA-induced differentiation. Overexpression of wild-type or dominant inhibitory mutant (D205N) of RSK1 enhanced or suppressed PMA-stimulated NF-kappaB activation and megakaryocytic differentiation as shown by morphology, nonspecific esterase activity, and expression of the CD41 megakaryocytic marker, respectively. In addition, overexpression of the dominant inhibitory mutant (S32A/S36A) of IkappaBalpha inhibited PMA-stimulated and RSK1-enhanced megakaryocytic differentiation, indicating that NF-kappaB mediates a signal for megakaryocytic differentiation downstream of RSK1. PMA-stimulated activation of ERK/MAPK, RSK1, and NF-kappaB and the PMA-induced megakaryocytic differentiation were prevented by pretreatment with PD98059, a specific inhibitor of the mitogen-activated ERK kinase (MEK). Therefore, these results demonstrate that the sequential ERK/RSK1/NF-kappaB pathway mediates PMA-stimulated megakaryocytic differentiation of K562 cells.
Department of Biochemistry, Research Center for Molecular Medicine, Pusan National University, Pusan 602-739, Korea.
K W
KW
Kim
S H
SH
Kim
E Y
EY
Lee
N D
ND
Kim
H S
HS
Kang
H D
HD
Kim
B S
BS
Chung
C D
CD
Kang
D019943:Amino Acid Substitution; D015703:Antigens, CD / Q000032:analysis; D002454:Cell Differentiation / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D039661:Integrin beta3; D020014:K562 Cells; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008533:Megakaryocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000378:metabolism*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000032:analysis; D010980:Platelet Membrane Glycoproteins / Q000032:analysis; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases / Q000737:chemistry / Q000378:metabolism*; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014162:Transfection
D015703:Antigens, CD; D004791:Enzyme Inhibitors; D005419:Flavonoids; D039661:Integrin beta3; D016328:NF-kappa B; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D010980:Platelet Membrane Glycoproteins; D011994:Recombinant Proteins; C069329:RPS6KA1 protein, human; D019893:Ribosomal Protein S6 Kinases; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one