14-3-3 epsilon dynamically interacts with key components of mitogen-activated protein kinase signal module for selective modulation of the TNF-alpha-induced time course-dependent NF-kappaB activity.
Inflammation is tightly regulated by nuclear factor-kappa B (NF-kappaB), and if left unchecked excessive NF-kappaB activation for cytokine overproduction can lead to various pathogenic consequences including carcinogenesis. A proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), can be used to explore possible mechanisms whereby unknown functional pathways modulate the NF-kappaB activity for regulating TNF-alpha-induced inflammation. Given the multifunctional nature of 14-3-3 family proteins and the recent finding of their presence in the TNF-alpha/NF-kappaB pathway network, we used a dual-tagging quantitative proteomic method to first profile the TNF-alpha-inducible interacting partners of 14-3-3 epsilon, the least characterized 14-3-3 isomer in the family. For the first time, we found that TNF-alpha stimulation enhances the interactions between 14-3-3 epsilon and some key components in the mitogen-activated protein kinase (MAPK) signal module which is located at the immediate upstream of NF-kappaB, including transforming growth factor-beta activated kinase-1 (TAK1) and its interacting protein, protein phosphatase 2C beta (PPM1B). By using confocal laser scanning, we observed the TNF-alpha-induced colocalizations among 14-3-3 epsilon, TAK1, and protein phosphatase 2C beta (PPM1B), and these interactions were also TNF-alpha-inducible in different cell types. Further, we found that during the full course of the cellular response to TNF-alpha, the interactions between 14-3-3 epsilon and these two proteins were dynamic and were closely correlated with the time course-dependent changes in NF-kappaB activity, suggesting that these 14-3-3 epsilon interactions are the critical points of convergence for TNF-alpha signaling for modulating NF-kappaB activity. We then postulated a mechanistic view describing how 14-3-3 epsilon coordinates its dynamic interactions with TAK1 and PPM1B for differentially modulating TNF-alpha-induced changes in NF-kappaB activity. By using bioinformatics tools, we constructed the network involving most of the 14-3-3 epsilon interacting proteins identified in our proteomic study. We revealed that 14-3-3 epsilon coordinates the cross talks between the MAPK signal module and other molecular pathways/biological processes primarily including protein metabolism and synthesis, DNA repair, and cell cycle regulation where pharmacological targets for therapeutic intervention could be systematically located.
Zuo
Shuai
S
Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai, China.
Xue
Yan
Y
Tang
Siwei
S
Yao
Jun
J
Du
Ruyun
R
Yang
Pengyuan
P
Chen
Xian
X
D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D000074183:ATPases Associated with Diverse Cellular Activities; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D019295:Computational Biology / Q000379:methods*; D004265:DNA Helicases / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D018613:Microscopy, Confocal; D016328:NF-kappa B / Q000378:metabolism*; D009842:Oligopeptides; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D025941:Protein Interaction Mapping / Q000379:methods*; D000071636:Protein Phosphatase 2C; D015203:Reproducibility of Results; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D000099151:MAP Kinase Kinase Kinase 7
D048948:14-3-3 Proteins; D000074183:ATPases Associated with Diverse Cellular Activities; D002352:Carrier Proteins; D004265:DNA Helicases; D020930:MAP Kinase Kinase Kinases; D016328:NF-kappa B; D009842:Oligopeptides; D010455:Peptides; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C; D014409:Tumor Necrosis Factor-alpha; D000099151:MAP Kinase Kinase Kinase 7; C482983:YWHAE protein, human; C085706:FLAG peptide; C000607456:PPM1A protein, human; C000607457:PPM1B protein, human; C000607460:PPM1G protein, human; C122079:RUVBL2 protein, human