Project description:The analysis examined the effects of a global ERK1 and/or tamoxifen-inducible, hepatocyte-specific ERK2 knockout on the liver transcriptome. Transcriptomes from the livers with a ERK1/2 double knockout were compared to the livers of mice with an ERK1 or ERK2 knockout.
Project description:We knocked out ERK1 and ERK2 in the striatopallidal population of striatal medium spiny neurons and analyzed differences in gene expression at P17, a time of increased synapse formation. We used whole gene microarray to assess transcriptional changes that occur in the mouse striatum at P17 in response to ERK1/2 deletion in striatopallidal medium spiny neurons.
Project description:Angiogenesis is a complex process orchestrated by both growth factors and cell adhesion to the extracellular matrix and is initiated by focal degradation of the vascular basement membrane with subsequent migration and proliferation of endothelial cells (EC). The Ras/Raf/MEK/ERK pathway is critical for EC function during angiogensis. Although in vitro studies implicate ERK1 and ERK2 in EC survival, their precise role in EC function in vivo remains poorly defined. Cre/loxP technology was used to inactivate Erk1 and Erk2 in EC during murine development, resulting in embryonic lethality due to a drastic reduction in angiogenesis. The angiogenic defect was linked to diminished EC proliferation and migration, but not to increased cell apoptosis. Expression of key cell cycle regulators was diminished in the double knockout cells. In addition, both Paxillin and Focal Adhesion Kinase were expressed at lower levels and failed to correctly localize to the cell membrane in EC lacking Erk1 and Erk2, leading to defects in the organization of the cytoskeleton and in cell motility. The results demonstrate that ERK1 and ERK2 coordinate cell proliferation and migration during angiogenesis. Lentivirus infected cells to generate ERK1/2 WT and ERK1/2 DKO endothelial cells were cultured, RNA was extracted and Affymetrix gene expression arrays were performed.
Project description:Angiogenesis is a complex process orchestrated by both growth factors and cell adhesion to the extracellular matrix and is initiated by focal degradation of the vascular basement membrane with subsequent migration and proliferation of endothelial cells (EC). The Ras/Raf/MEK/ERK pathway is critical for EC function during angiogensis. Although in vitro studies implicate ERK1 and ERK2 in EC survival, their precise role in EC function in vivo remains poorly defined. Cre/loxP technology was used to inactivate Erk1 and Erk2 in EC during murine development, resulting in embryonic lethality due to a drastic reduction in angiogenesis. The angiogenic defect was linked to diminished EC proliferation and migration, but not to increased cell apoptosis. Expression of key cell cycle regulators was diminished in the double knockout cells. In addition, both Paxillin and Focal Adhesion Kinase were expressed at lower levels and failed to correctly localize to the cell membrane in EC lacking Erk1 and Erk2, leading to defects in the organization of the cytoskeleton and in cell motility. The results demonstrate that ERK1 and ERK2 coordinate cell proliferation and migration during angiogenesis.
Project description:Extracellular signal regulated kinases, ERK1 and ERK2 are often considered as redundant due to their high homology, large number of overlapping substrates, and ability to substitute for each other in genetically engineered mouse models. We have investigated the individual contribution of ERK1 and ERK2 to the survival of human melanoma cell lines driven by oncogenic BRAF. ERK2, but not ERK1 activity, was crucial to drive survival and maintain transcriptional output of the MAPK pathway. Furthermore, we found that ERK2 DEF-domain interactions were crucial for transcriptional regulation and survival in some cells, but not in others, whereas ERK2-substrate interactions at the D-docking motif were largely dispensable. We used microarrays to examine the global impact of gene expression by imhibiting different nodes of MAPK pathway.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
Project description:Activation of ERK1 and ERK2 is essential in regulation of a wide variety of cellular and physiological processes. In native inner medullary collecting ducts, vasopressin (AVP) working through the V2 subtype vasopressin receptor (V2R)-mediated activation of Gαs, inhibits ERK1 and ERK2 activity. However, it has been reported that V2R can signal independently of Gαs through the activation of β-arrestin, which activates ERK1 and ERK2. Vaptans, V2R antagonists that function as so-called “inverse agonists”, have the potential of promoting cell proliferation via β-arrestin-dependent ERK activation. Here we use the mpkCCD cell line which natively expresses V2R to investigate the effects of AVP, the V2-selective analog dDAVP, and tolvaptan on ERK1 and ERK2 phosphorylation and activation. We demonstrated that ERK1 and ERK2 phosphorylation in mpkCCD cells was significantly reduced by either AVP or dDAVP, in contrast to the increases seen in non-collecting duct cells overexpressing V2R. We also found that tolvaptan has a strong effect to increase ERK1 and ERK2 phosphorylation in the presence of dDAVP and that the tolvaptan effect to increase ERK1 and ERK2 phosphorylation is absent in PKA-null mpkCCD cells. Thus, it appears that the tolvaptan effect to increase ERK activation is PKA-dependent and, therefore, not mediated by the β-arrestin pathway. Overall, the studies show that AVP decreases and that tolvaptan increases ERK1 and ERK2 activation in cells expressing V2R at endogenous levels, and provide no evidence for a role for β-arrestin in the regulation of ERK1 and ERK2 activity.
Project description:Activation of ERK1 and ERK2 is essential in regulation of a wide variety of cellular and physiological processes. In native inner medullary collecting ducts, vasopressin (AVP) working through the V2 subtype vasopressin receptor (V2R)-mediated activation of Gαs, inhibits ERK1 and ERK2 activity. However, it has been reported that V2R can signal independently of Gαs through the activation of β-arrestin, which activates ERK1 and ERK2. Vaptans, V2R antagonists that function as so-called “inverse agonists”, have the potential of promoting cell proliferation via β-arrestin-dependent ERK activation. Here we use the mpkCCD cell line which natively expresses V2R to investigate the effects of AVP, the V2-selective analog dDAVP, and tolvaptan on ERK1 and ERK2 phosphorylation and activation. We demonstrated that ERK1 and ERK2 phosphorylation in mpkCCD cells was significantly reduced by either AVP or dDAVP, in contrast to the increases seen in non-collecting duct cells overexpressing V2R. We also found that tolvaptan has a strong effect to increase ERK1 and ERK2 phosphorylation in the presence of dDAVP and that the tolvaptan effect to increase ERK1 and ERK2 phosphorylation is absent in PKA-null mpkCCD cells. Thus, it appears that the tolvaptan effect to increase ERK activation is PKA-dependent and, therefore, not mediated by the β-arrestin pathway. Overall, the studies show that AVP decreases and that tolvaptan increases ERK1 and ERK2 activation in cells expressing V2R at endogenous levels, and provide no evidence for a role for β-arrestin in the regulation of ERK1 and ERK2 activity.