Smads, TAK1, and their common target ATF-2 play a critical role in cardiomyocyte differentiation.
We previously demonstrated that bone morphogenetic proteins (BMPs) induce cardiomyocyte differentiation through the mitogen-activated protein kinase kinase kinase TAK1. Transcription factors Smads mediate transforming growth factor-beta signaling and the ATF/CREB family transcription factor ATF-2 has recently been shown to act as a common target of the Smad and the TAK1 pathways. We here examined the role of Smads and ATF-2 in cardiomyocyte differentiation of P19CL6, a clonal derivative of murine P19 cells. Although P19CL6 efficiently differentiates into cardiomyocytes when treated with dimethyl sulfoxide, P19CL6noggin, a P19CL6 cell line constitutively overexpressing the BMP antagonist noggin, did not differentiate into cardiomyocytes. Cooverexpression of Smad1, a ligand-specific Smad, and Smad4, a common Smad, restored the ability of P19CL6noggin to differentiate into cardiomyocytes, whereas stable overexpression of Smad6, an inhibitory Smad, completely blocked differentiation of P19CL6, suggesting that the Smad pathway is necessary for cardiomyocyte differentiation. ATF-2 stimulated the betaMHC promoter activity by the synergistic manner with Smad1/4 and TAK1 and promoted terminal cardiomyocyte differentiation of P19CL6noggin, whereas overexpression of the dominant negative form of ATF-2 reduced the promoter activities of several cardiac-specific genes and inhibited differentiation of P19CL6. These results suggest that Smads, TAK1, and their common target ATF-2 cooperatively play a critical role in cardiomyocyte differentiation.
Monzen
K
K
Department of Cardiovascular Medicine, University of Tokyo Graduate School of Medicine, Tokyo 113-8655, Japan.
Hiroi
Y
Y
Kudoh
S
S
Akazawa
H
H
Oka
T
T
Takimoto
E
E
Hayashi
D
D
Hosoda
T
T
Kawabata
M
M
Miyazono
K
K
Ishii
S
S
Yazaki
Y
Y
Nagai
R
R
Komuro
I
I
D051698:Activating Transcription Factor 2; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D018485:Muscle Fibers, Skeletal / Q000166:cytology* / Q000201:enzymology; D009206:Myocardium / Q000166:cytology*; D011506:Proteins / Q000235:genetics; D051785:Smad Proteins; D051905:Smad6 Protein; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D000099176:Noggin Protein
D051698:Activating Transcription Factor 2; D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D051785:Smad Proteins; D051905:Smad6 Protein; D015534:Trans-Activators; D014157:Transcription Factors; D000099176:Noggin Protein; C099510:TAB1 protein, MAPKKK activator, vertebrate; C486300:TAB1 protein, human