GADD45beta enhances Col10a1 transcription via the MTK1/MKK3/6/p38 axis and activation of C/EBPbeta-TAD4 in terminally differentiating chondrocytes.
GADD45beta (growth arrest- and DNA damage-inducible) interacts with upstream regulators of the JNK and p38 stress response kinases. Previously, we reported that the hypertrophic zone of the Gadd45beta(-/-) mouse embryonic growth plate is compressed, and expression of type X collagen (Col10a1) and matrix metalloproteinase 13 (Mmp13) genes is decreased. Herein, we report that GADD45beta enhances activity of the proximal Col10a1 promoter, which contains evolutionarily conserved AP-1, cAMP-response element, and C/EBP half-sites, in synergism with C/EBP family members, whereas the MMP13 promoter responds to GADD45beta together with AP-1, ATF, or C/EBP family members. C/EBPbeta expression also predominantly co-localizes with GADD45beta in the embryonic growth plate. Moreover, GADD45beta enhances C/EBPbeta activation via MTK1, MKK3, and MKK6, and dominant-negative p38alphaapf, but not JNKapf, disrupts the combined trans-activating effect of GADD45beta and C/EBPbeta on the Col10a1 promoter. Importantly, GADD45beta knockdown prevents p38 phosphorylation while decreasing Col10a1 mRNA levels but does not affect C/EBPbeta binding to the Col10a1 promoter in vivo, indicating that GADD45beta influences the transactivation function of DNA-bound C/EBPbeta. In support of this conclusion, we show that the evolutionarily conserved TAD4 domain of C/EBPbeta is the target of the GADD45beta-dependent signaling. Collectively, we have uncovered a novel molecular mechanism linking GADD45beta via the MTK1/MKK3/6/p38 axis to C/EBPbeta-TAD4 activation of Col10a1 transcription in terminally differentiating chondrocytes.
Tsuchimochi
Kaneyuki
K
Laboratory for Cartilage Biology, Research Division, The Hospital for Special Surgery, Weill Cornell Medical College, New York, New York 10021, USA.
Otero
Miguel
M
Dragomir
Cecilia L
CL
Plumb
Darren A
DA
Zerbini
Luiz F
LF
Libermann
Towia A
TA
Marcu
Kenneth B
KB
Komiya
Setsuro
S
Ijiri
Kosei
K
Goldring
Mary B
MB
D051697:Activating Transcription Factor 1 / Q000378:metabolism; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism*; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D045744:Cell Line, Tumor; D019902:Chondrocytes / Q000166:cytology* / Q000502:physiology*; D024121:Collagen Type X / Q000235:genetics*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006132:Growth Plate / Q000166:cytology / Q000196:embryology / Q000502:physiology; D006801:Humans; D048371:MAP Kinase Kinase 3 / Q000378:metabolism; D048669:MAP Kinase Kinase 6 / Q000378:metabolism; D048728:MAP Kinase Kinase Kinase 1 / Q000378:metabolism; D048768:MAP Kinase Kinase Kinase 4 / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D053509:Matrix Metalloproteinase 13 / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D011401:Promoter Regions, Genetic / Q000502:physiology; D018243:Teratocarcinoma; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000097642:GADD45 Proteins
D051697:Activating Transcription Factor 1; D000943:Antigens, Differentiation; D022782:CCAAT-Enhancer-Binding Protein-beta; D024121:Collagen Type X; D017362:Cyclic AMP Response Element-Binding Protein; D048371:MAP Kinase Kinase 3; D048669:MAP Kinase Kinase 6; D048728:MAP Kinase Kinase Kinase 1; D048768:MAP Kinase Kinase Kinase 4; D053509:Matrix Metalloproteinase 13; D018808:Transcription Factor AP-1; D048051:p38 Mitogen-Activated Protein Kinases; C497100:Atf1 protein, mouse; C545013:Cebpb protein, mouse; C492004:Creb1 protein, mouse; C490125:Gadd45b protein, mouse; D000097642:GADD45 Proteins; C482531:Map2k3 protein, mouse; C482567:Map2k6 protein, mouse; C507081:Mmp13 protein, mouse