scholarly journals Involvement of JunD in transcriptional activation of the orphan receptor gene nur77 by nerve growth factor and membrane depolarization in PC12 cells

1994 ◽  
Vol 14 (12) ◽  
pp. 7731-7743
Author(s):  
J K Yoon ◽  
L F Lau
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Transcriptional Activation ◽  
Membrane Depolarization ◽  
Dominant Negative ◽  
Orphan Receptor ◽  
Early Gene ◽  
Dominant Negative Mutant ◽  
Transcription Activator ◽  
Nerve Growth

nur77, an immediate-early gene that encodes an orphan nuclear receptor, is rapidly and transiently induced by nerve growth factor (NGF) stimulation or membrane depolarization in the rat pheochromocytoma-derived cell line PC12. The Nur77 protein can act as a potent transcription activator and may function to regulate the expression of downstream genes in response to extracellular stimuli. We show here that activation of nur77 by NGF treatment and membrane depolarization is signalled through distinct pathways. These distinct signals appear to converge on the same transcription factors acting on the same promoter elements. We show that nur77 activation by both processes requires two cis-acting AP1-like elements, NAP1 and NAP2, which contain the core sequence TGCGTCA centered at 67 and 38 nucleotides upstream of the transcription start site. The NAP elements can confer inducibility by NGF and membrane depolarization on an otherwise unresponsive heterologous promoter. We identified JunD as a key mediator of nur77 activation by reason of the following observations. (i) JunD, but not CREB or other members of the Fos/Jun family, is a component of NAP binding activity in PC12 cell nuclear extracts. (ii) JunD, but not other Fos/Jun family members, specifically transactivates the nur77 promoter through the NAP elements (iii) A dominant-negative mutant of JunD effectively abolishes the activation of nur77 by either NGF treatment or membrane depolarization. These data draw a contrast between the regulation of nur77 with that of c-fos, in which the sequence requirements for activation by NGF treatment and membrane depolarization appear separable, and CREB appears to play a role in activation by both NGF and membrane depolarization.

scholarly journals Involvement of JunD in transcriptional activation of the orphan receptor gene nur77 by nerve growth factor and membrane depolarization in PC12 cells.

1994 ◽  
Vol 14 (12) ◽  
pp. 7731-7743 ◽  
Author(s):  
J K Yoon ◽  
L F Lau
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Transcriptional Activation ◽  
Membrane Depolarization ◽  
Dominant Negative ◽  
Orphan Receptor ◽  
Early Gene ◽  
Dominant Negative Mutant ◽  
Transcription Activator ◽  
Nerve Growth

nur77, an immediate-early gene that encodes an orphan nuclear receptor, is rapidly and transiently induced by nerve growth factor (NGF) stimulation or membrane depolarization in the rat pheochromocytoma-derived cell line PC12. The Nur77 protein can act as a potent transcription activator and may function to regulate the expression of downstream genes in response to extracellular stimuli. We show here that activation of nur77 by NGF treatment and membrane depolarization is signalled through distinct pathways. These distinct signals appear to converge on the same transcription factors acting on the same promoter elements. We show that nur77 activation by both processes requires two cis-acting AP1-like elements, NAP1 and NAP2, which contain the core sequence TGCGTCA centered at 67 and 38 nucleotides upstream of the transcription start site. The NAP elements can confer inducibility by NGF and membrane depolarization on an otherwise unresponsive heterologous promoter. We identified JunD as a key mediator of nur77 activation by reason of the following observations. (i) JunD, but not CREB or other members of the Fos/Jun family, is a component of NAP binding activity in PC12 cell nuclear extracts. (ii) JunD, but not other Fos/Jun family members, specifically transactivates the nur77 promoter through the NAP elements (iii) A dominant-negative mutant of JunD effectively abolishes the activation of nur77 by either NGF treatment or membrane depolarization. These data draw a contrast between the regulation of nur77 with that of c-fos, in which the sequence requirements for activation by NGF treatment and membrane depolarization appear separable, and CREB appears to play a role in activation by both NGF and membrane depolarization.

scholarly journals ΔNp73 Modulates Nerve Growth Factor-Mediated Neuronal Differentiation through Repression of TrkA

2007 ◽  
Vol 27 (10) ◽  
pp. 3868-3880 ◽  
Author(s):  
Jin Zhang ◽  
Xinbin Chen
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neuronal Differentiation ◽  
Pc12 Cells ◽  
Trichostatin A ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
P53 Family ◽  
Nerve Growth ◽  
Histone Deacetylase 1

ABSTRACT p73, a member of the p53 family, expresses two classes of proteins: the full-length TAp73 and the N-terminally truncated ΔNp73. While TAp73 possesses many p53-like features, ΔNp73 is dominant negative towards TAp73 and p53 and appears to have distinct functions in tumorigenesis and neuronal development. Given its biological importance, we investigated the role of ΔNp73 in nerve growth factor (NGF)-mediated neuronal differentiation in PC12 cells. We show that overexpression of ΔNp73α or ΔNp73β inhibits NGF-mediated neuronal differentiation in both p53-dependent and -independent manners. In line with this, we showed that the level of endogenous ΔNp73 is progressively diminished in differentiating PC12 cells upon NGF treatment and knockdown of ΔNp73 promotes NGF-mediated neuronal differentiation. Interestingly, we found that the ability of ΔNp73 to suppress NGF-mediated neuronal differentiation is correlated with its ability to regulate the expression of TrkA, the high-affinity NGF receptor. Specifically, we found that ΔNp73 directly binds to the TrkA promoter and transcriptionally represses TrkA expression, which in turn attenuates the NGF-mediated mitogen-activated protein kinase pathway. Conversely, the steady-state level of TrkA is increased upon knockdown of ΔNp73. Furthermore, we found that histone deacetylase 1 (HDAC1) and HDAC2 are recruited by ΔNp73 to the TrkA promoter and act as corepressors to suppress TrkA expression, which can be relieved by trichostatin A, an HDAC inhibitor. Taken together, we conclude that ΔNp73 negatively regulates NGF-mediated neuronal differentiation by transrepressing TrkA.

scholarly journals Nerve Growth Factor-mediated Neurite Outgrowth via Regulation of Rab5

2007 ◽  
Vol 18 (4) ◽  
pp. 1375-1384 ◽  
Author(s):  
Jay Liu ◽  
Darija Lamb ◽  
Margaret M. Chou ◽  
Yong-Jian Liu ◽  
Guangpu Li
Keyword(s):  
Nerve Growth Factor ◽  
Rna Interference ◽  
Growth Factor ◽  
Neurite Outgrowth ◽  
Cellular Level ◽  
Early Endosome ◽  
Dominant Negative ◽  
Nerve Growth ◽  
Truncation Mutant ◽  
Ngf Signaling

Nerve growth factor (NGF) induces neurite outgrowth and differentiation in a process that involves NGF binding to its receptor TrkA and endocytosis of the NGF–TrkA complex into signaling endosomes. Here, we find that biogenesis of signaling endosomes requires inactivation of Rab5 to block early endosome fusion. Expression of dominant-negative Rab5 mutants enhanced NGF-mediated neurite outgrowth, whereas a constitutively active Rab5 mutant or Rabex-5 inhibited this process. Consistently, inactivation of Rab5 sustained TrkA activation on the endosomes. Furthermore, NGF treatment rapidly decreased cellular level of active Rab5-GTP, as shown by pull-down assays. This Rab5 down-regulation was mediated by RabGAP5, which was shown to associate with TrkA by coimmunoprecipitation assays. Importantly, RNA interference of RabGAP5 as well as a RabGAP5 truncation mutant containing the TrkA-binding domain blocked NGF-mediated neurite outgrowth, indicating a requirement for RabGAP5 in this process. Thus, NGF signaling down-regulates Rab5 activity via RabGAP5 to facilitate neurite outgrowth and differentiation.

scholarly journals Mapping of Atypical Protein Kinase C within the Nerve Growth Factor Signaling Cascade: Relationship to Differentiation and Survival of PC12 Cells

2000 ◽  
Vol 20 (13) ◽  
pp. 4494-4504 ◽  
Author(s):  
Marie W. Wooten ◽  
M. Lamar Seibenhener ◽  
Kimberly B. W. Neidigh ◽  
Michel L. Vandenplas
Keyword(s):  
Protein Kinase C ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Protein Kinase ◽  
Pc12 Cells ◽  
Dominant Negative ◽  
Atypical Protein Kinase C ◽  
Nerve Growth ◽  
Atypical Protein Kinase ◽  
Kinase C

ABSTRACT The pathway by which atypical protein kinase C (aPKC) contributes to nerve growth factor (NGF) signaling is poorly understood. We previously reported that in PC12 cells NGF-induced activation of mitogen-activated protein kinase (MAPK) occurs independently of classical and nonclassical PKC isoforms, whereas aPKC isoforms were shown to be required for NGF-induced differentiation. NGF-induced activation of PKC-ι was observed to be dependent on phosphatidylinositol 3-kinase (PI3K) and led to coassociation of PKC-ι with Ras and Src. Expression of dominant negative mutants of either Src (DN2) or Ras (Asn-17) impaired activation of PKC-ι by NGF. At the level of Raf-1, neither PKC-ι nor PI3 kinase was required for activation; however, PKC-ι could weakly activate MEK. Inhibitors of PKC-ι activity and PI3K had no effect on NGF-induced MAPK or p38 activation but reduced NGF-stimulated c-Jun N-terminal kinase activity. Src, PI3K, and PKC-ι were likewise required for NGF-induced NF-κB activation and cell survival, whereas Ras was not required for either survival or NF-κB activation but was required for differentiation. IKK existed as a complex with PKC-ι, Src and IκB. Consistent with a role for Src in regulating NF-κB activation, an absence of Src activity impaired recruitment of PKC-ι into an IKK complex and markedly impaired NGF-induced translocation of p65/NF-κB to the nucleus. These findings reveal that in PC12 cells, aPKCs comprise a molecular switch to regulate differentiation and survival responses coupled downstream to NF-κB. On the basis of these findings, Src emerges as a critical upstream regulator of both PKC-ι and the NF-κB pathway.

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