Transformation of Mammalian Cells by Constitutively Active MAP Kinase Kinase

Mansour, Sam J.; Matten, Wayne T.; Hermann, April S.; Candia, Julian M.; Rong, Sing; Fukasawa, Kenji; Woude, George F. Vande; Ahn, Natalie G.

doi:10.1126/science.8052857

Cited by 1,310 publications

(1,133 citation statements)

References 44 publications

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“…Both T507K SHP-2 and the leukemia-specific E76K SHP-2 are capable of eliciting aberrant activation of RAF1. Although constitutive activation of the RAS-RAF-ERK pathway intimately relates with NIH3T3 transformation (Mansour et al, 1994), the failure of E76K SHP-2 to transform NIH3T3 cells indicates that aberrant activation of the RAS-RAF-ERK pathway per se is not sufficient for the transformation of NIH3T3 cells. In this regard, we also investigated the effects of wild-type SHP-2, T507K SHP-2 and E76K SHP-2 on another RAS-effector pathway, the PI3K-AKT pathway and found that none of these SHP-2 mutants significantly modifies AKT activity when expressed in NIH3T3 cells (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Isolation of a distinct class of gain-of-function SHP-2 mutants with oncogenic RAS-like transforming activity from solid tumors

Miyamoto

Takahashi

et al. 2008

Oncogene

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Section: Discussionmentioning

confidence: 99%

Isolation of a distinct class of gain-of-function SHP-2 mutants with oncogenic RAS-like transforming activity from solid tumors

Miyamoto

Takahashi

et al. 2008

Oncogene

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“…Compared to pBabe cells, HU produced higher levels of Erk activation in MEK1Q56P cells, which requires higher doses of U0126, the most potent MEK inhibitor (Krepinsky et al, 2002), to block the Erk activation (Figure 1b). Conversely, ectopic expression of a dominant-negative mutant MEK1 (MEK1K97M) (Mansour et al, 1994) attenuated HUinduced Erk activation (Figure 1c). Taken together, these data reveal that MEK1 plays a role in HU-induced Erk activation.…”

Section: Hu Activates Erk Kinase Via Mek1mentioning

confidence: 99%

ERK activity facilitates activation of the S-phase DNA damage checkpoint by modulating ATR function

Chen

Parihar

et al. 2005

Oncogene

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Although Erk kinase has been recently reported to function in the DNA damage response, the mechanism governing this process is unknown. We report here that hydroxyurea (HU) activates Erk via MEK1, a process that is sensitized by a constitutively active MEK1 (MEK1Q56P) and attenuated by a dominant-negative MEK1 (MEK1K97M). While ectopic MEK1Q56P sensitized HU-induced S-phase arrest, inhibition of Erk activation via U0126, PD98059, and MEK1K97M attenuated the arrest, and thereby enhanced cells to HU-induced toxicity. Taken together, we demonstrate an important contribution of Erk to the activation of the S-phase DNA damage checkpoint. This can be attributed to Erk's regulatory role in modulating ATR function. Inhibition of Erk activation with U0126/PD98059 and MEK1K97M substantially reduced HU-induced ATR nuclear foci, leading to a dramatic reduction of cH2AX and its nuclear foci. Reduction of MEK1 function by a small interference RNA (siRNA) MEK1 and ectopic MEK1K97M significantly decreased HU-induced cH2AX. Conversely, ectopic MEK1Q56P enhanced cH2AX foci. Furthermore, immunofluorescent and cell fractioning experiments revealed cytosolic and nuclear localization of ATR. HU treatment caused the redistribution of ATR from the cytosol to the nucleus, a process that is inhibited by U0126. Collectively, we show that Erk kinase modulates HU-initiated DNA damage response by regulating ATR function.

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“…To determine the point at which LIMK1 inhibits the Ras-induced di erentiation signaling pathway, we examined the e ect of overexpression of DK-HA on activated MAPKK-induced di erentiation of PC12 cells. The expression plasmid pRc-CMV-DNSESE containing Xenopus DNSESE was used for expression of constitutively activated MAPKK, in which the Nterminal negative regulation domain (residues 32 ± 51) was deleted and two activating phosphorylation sites (Ser218 and Ser222) were replaced by glutamic acid residues (Gotoh et al, 1995;Mansour et al, 1994). In the transient transfection assay with the b-Gal reporter plasmid, DNSESE induced neuronal di erentiation of PC12 cells in 57% of blue cells (Figure 3).…”

Section: Constitutively Activated Mapkk-induced Pc12 DI Erentiation Imentioning

confidence: 99%

Inhibition of activated Ras-induced neuronal differentiation of PC12 cells by the LIM domain of LIM-kinase 1

et al. 1997

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LIM-kinase 1 and 2 (LIMK1 and LIMK2) are members of a novel class of protein kinases with structures composed of two LIM motifs at the N-terminus and an unusual protein kinase domain at the C-terminus. The cellular functions of the LIMK family proteins have remained unknown. In the present study, we examined e ects of LIMKs on neuronal di erentiation of PC12 pheochromocytoma cells. Transient expression analyses revealed that LIMK1, in itself, had no apparent e ect on PC12 cells, but the oncogenic Ras-induced di erentiation of PC12 cells was notably inhibited by co-expression with LIMK1 or LIMK2. A mutant of LIMK1 lacking a protein kinase domain (DK) similarly inhibited Rasinduced di erentiation of PC12 cells, but a mutant lacking a LIM domain (DLIM) failed to do so, indicating that a LIM domain but not a protein kinase domain is required for the inhibitory activity. This notion was further supported by the ®nding that mutation, changing conserved cysteines involved in zinc coordination to glycines in both of two LIM motifs, abolished the inhibitory activity of DK. Additionally, we also found that the constitutively activated MAP kinase kinase (MAPKK)-induced di erentiation of PC12 cells was inhibited by co-expression with DK. Furthermore, DK did not inhibit the kinase activity of MAP kinase (MAPK) stimulated by MAPKK, when co-expressed in COS7 cells. These ®ndings suggest that LIMK1 inhibits neuronal di erentiation of PC12 cells, through its LIM domain and by interfering with events downstream of MAPK activation.

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Transformation of Mammalian Cells by Constitutively Active MAP Kinase Kinase

Cited by 1,310 publications

References 44 publications

Isolation of a distinct class of gain-of-function SHP-2 mutants with oncogenic RAS-like transforming activity from solid tumors

Isolation of a distinct class of gain-of-function SHP-2 mutants with oncogenic RAS-like transforming activity from solid tumors

ERK activity facilitates activation of the S-phase DNA damage checkpoint by modulating ATR function

Inhibition of activated Ras-induced neuronal differentiation of PC12 cells by the LIM domain of LIM-kinase 1

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