Differential activation of stress-activated protein kinase kinases SKK4/MKK7 and SKK1/MKK4 by the mixed-lineage kinase-2 and mitogen-activated protein kinase kinase (MKK) kinase-1.
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ABSTRACT:
SUBMITTER: Cuenda A
PROVIDER: S-EPMC1219549 | biostudies-other | 1998 Jul
REPOSITORIES: biostudies-other
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Project description:Signal transduction pathways are integral components of the developmental regulatory network that guides progressive cell fate determination. MKK4 and MKK7 are upstream kinases of the mitogen-activated protein kinases (MAPKs), responsible for channeling physiological and environmental signals to their cellular responses. Both kinases are essential for survival of mouse embryos, but because of embryonic lethality, their precise developmental roles remain largely unknown. Using gene knock-out mouse ESCs, we studied the roles of MKK4 and MKK7 in differentiation in vitro. While MKK4 and MKK7 were dispensable for ESC self-renewal and pluripotency maintenance, they exhibited unique signaling and functional properties in differentiation. MKK4 and MKK7 complemented each other in activation of the JNK-c-Jun cascades and loss of both led to senescence upon cell differentiation. On the other hand, MKK4 and MKK7 had opposite effects on activation of the p38 cascades during differentiation. Specifically, MKK7 reduced p38 activation, while Mkk7(-/-) ESCs had elevated phosphorylation of MKK4, p38, and ATF2, and increased MEF2C expression. Consequently, Mkk7(-/-) ESCs had higher expression of MHC and MLC and enhanced formation of contractile cardiomyocytes. In contrast, MKK4 was required for p38 activation and Mkk4(-/-) ESCs exhibited diminished p-ATF2 and MEF2C expression, resulting in impaired MHC induction and defective cardiomyocyte differentiation. Exogenous MKK4 expression partially restored the ability of Mkk4(-/-) ESCs to differentiate into cardiomyocytes. Our results uncover complementary and interdependent roles of MKK4 and MKK7 in development, and identify the essential requirement for MKK4 in p38 activation and cardiomyocyte differentiation.
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Project description:Acetaminophen (APAP), a widely used analgesic and antipyretic that is considered to be relatively safe at recommended doses, is the leading cause of drug-induced liver failure in the United States. 3M-bM-^@M-^Y-Hydroxyacetanilide (AMAP), a regioisomer of acetaminophen is useful as a comparative tool for studying APAP-induced toxicity since it is non-toxic relative to APAP. TGF-alpha transgenic mouse hepatocytes were treated with both isomers to investigate mitogen-activated protein kinase cascades in order to differentiate their toxicological outcomes. Mitogen-activated protein kinase (MAPK) cascade expression and activation were measured using microarray and Bioplex technologies, respectively. APAP treatment led to c-Jun N-terminal kinase (JNK) activation, whereas AMAP treatment led to the activation of extracellular-signal-regulated protein kinase (ERK). The microarray data suggested APAP treatment may upregulate gene expression at multiple levels of the JNK cascade including a JNK-related scaffold protein. Expression data was related to phosphoprotein levels using the Bioplex system. APAP treatment led to a significant activation of JNK compared to its regioisomer. In contrast, microarray analysis of AMAP showed a slight upregulation of ERK gene activity. Furthermore, Bioplex data showed AMAP treatment led to significant ERK phosphorylation compared to APAP. Cell viability assays confirmed that APAP-induced activation of JNK was related to higher rates of cell death, whereas activation of ERK by AMAP may be cytoprotective. 27 arrays, 9 experimental groups, 2hr AMAP, 2hr APAP, 2hr Control, 6hr AMAP, 6hr APAP, 6hr Control, 24hr AMAP, 24hr APAP, 24hr Control.
2010-07-06 | E-GEOD-18614 | biostudies-arrayexpress
Project description:Acetaminophen (APAP), a widely used analgesic and antipyretic that is considered to be relatively safe at recommended doses, is the leading cause of drug-induced liver failure in the United States. 3’-Hydroxyacetanilide (AMAP), a regioisomer of acetaminophen is useful as a comparative tool for studying APAP-induced toxicity since it is non-toxic relative to APAP. TGF-alpha transgenic mouse hepatocytes were treated with both isomers to investigate mitogen-activated protein kinase cascades in order to differentiate their toxicological outcomes. Mitogen-activated protein kinase (MAPK) cascade expression and activation were measured using microarray and Bioplex technologies, respectively. APAP treatment led to c-Jun N-terminal kinase (JNK) activation, whereas AMAP treatment led to the activation of extracellular-signal-regulated protein kinase (ERK). The microarray data suggested APAP treatment may upregulate gene expression at multiple levels of the JNK cascade including a JNK-related scaffold protein. Expression data was related to phosphoprotein levels using the Bioplex system. APAP treatment led to a significant activation of JNK compared to its regioisomer. In contrast, microarray analysis of AMAP showed a slight upregulation of ERK gene activity. Furthermore, Bioplex data showed AMAP treatment led to significant ERK phosphorylation compared to APAP. Cell viability assays confirmed that APAP-induced activation of JNK was related to higher rates of cell death, whereas activation of ERK by AMAP may be cytoprotective.
2010-07-07 | GSE18614 | GEO
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