Regulation of myeloid zinc finger protein 2A transactivation activity through phosphorylation by mitogen-activated protein kinases.
The myeloid zinc finger protein (MZF)-2 is a C(2)H(2) zinc finger transcription factor that is expressed in myeloid cells and involved in the growth, differentiation, and tumorigenesis of myeloid progenitors. Here we describe a novel isoform of MZF-2, designated MZF-2A, and show that it is phosphorylated by the mitogen-activated protein (MAP) kinases. An in vitro phosphorylation experiment revealed that the transactivation domain (TAD) of MZF-2A was phosphorylated strongly by extracellular signal-regulated kinase (ERK) and phosphorylated weakly by p38 MAP kinase but not by Jun N-terminal kinase. Experiments using "add-back" mutants showed that three serine residues (Ser(257), Ser(275), and Ser(295)) in the TAD were phosphorylated in vitro by ERK. In myeloid LGM-1 cells, various extracellular stimuli induced the phosphorylation of these serine residues, which was differentially inhibited by the protein kinase inhibitors U0126 and SB203580. Substitution of these phosphorylation sites with alanines resulted in a strong enhancement of the ability of MZF-2A to activate transcription in a luciferase reporter assay. Taken together, these results indicate that MZF-2A is a novel target for the ERK and p38 MAP kinase signaling pathways, and its transactivation activity is negatively regulated by MAP kinase-mediated phosphorylation of the TAD.
Ogawa
Hironori
H
Department of Genetics B-3, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Murayama
Ayako
A
Nagata
Shigekazu
S
Fukunaga
Rikiro
R
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D016179:Granulocyte Colony-Stimulating Factor / Q000235:genetics; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D051741:Kruppel-Like Transcription Factors; D020935:MAP Kinase Signaling System / Q000502:physiology; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D018411:Spodoptera; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D051741:Kruppel-Like Transcription Factors; C085969:MZF1 protein, human; C490095:Mzf1 protein, mouse; D020033:Protein Isoforms; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D016179:Granulocyte Colony-Stimulating Factor; D048031:JNK Mitogen-Activated Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases