scholarly journals Rab22 controls NGF signaling and neurite outgrowth in PC12 cells

2011 ◽  
Vol 22 (20) ◽  
pp. 3853-3860 ◽  
Author(s):  
Liang Wang ◽  
Zhimin Liang ◽  
Guangpu Li
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Small Gtpase ◽  
Rab Gtpase ◽  
Early Endosomes ◽  
Ngf Signaling

Rab22 is a small GTPase that is localized on early endosomes and regulates early endosomal sorting. This study reports that Rab22 promotes nerve growth factor (NGF) signaling-dependent neurite outgrowth and gene expression in PC12 cells by sorting NGF and the activated/phosphorylated receptor (pTrkA) into signaling endosomes to sustain signal transduction in the cell. NGF binding induces the endocytosis of pTrkA into Rab22-containing endosomes. Knockdown of Rab22 via small hairpin RNA (shRNA) blocks NGF-induced pTrkA endocytosis into the endosomes and gene expression (VGF) and neurite outgrowth. Overexpression of human Rab22 can rescue the inhibitory effects of the Rab22 shRNA, suggesting a specific Rab22 function in NGF signal transduction, rather than off-target effects. Furthermore, the Rab22 effector, Rabex-5, is necessary for NGF-induced neurite outgrowth and gene expression, as evidenced by the inhibitory effect of shRNA-mediated knockdown of Rabex-5. Disruption of the Rab22–Rabex-5 interaction via overexpression of the Rab22-binding domain of Rabex-5 in the cell also blocks NGF-induced neurite outgrowth, suggesting a critical role of Rab22–Rabex-5 interaction in the biogenesis of NGF-signaling endosomes to sustain the signal for neurite outgrowth. These data provide the first evidence for an early endosomal Rab GTPase as a positive regulator of NGF signal transduction and cell differentiation.

The catalytic activity, but not receptor binding, of sPLA2s plays a critical role for neurite outgrowth induction in PC12 cells

2004 ◽  
Vol 1015 (1-2) ◽  
pp. 207-211 ◽  
Author(s):  
Satoru Nakashima ◽  
Katsuhiko Kitamoto ◽  
Manabu Arioka
Keyword(s):  
Catalytic Activity ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Receptor Binding ◽  
Critical Role

scholarly journals Overexpression of HuD, but Not of Its Truncated Form HuD I+II, Promotes GAP-43 Gene Expression and Neurite Outgrowth in PC12 Cells in the Absence of Nerve Growth Factor

2002 ◽  
Vol 75 (3) ◽  
pp. 1103-1114 ◽  
Author(s):  
Kim D. Anderson ◽  
Melissa A. Morin ◽  
Andrea Beckel-Mitchener ◽  
Charlotte D. Mobarak ◽  
Rachael L. Neve ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Truncated Form ◽  
Nerve Growth

scholarly journals Rab4 Regulates Formation of Synaptic-like Microvesicles from Early Endosomes in PC12 Cells

2001 ◽  
Vol 12 (11) ◽  
pp. 3703-3715 ◽  
Author(s):  
Heidi de Wit ◽  
Yael Lichtenstein ◽  
Regis B. Kelly ◽  
Hans J. Geuze ◽  
Judith Klumperman ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pc12 Cells ◽  
Early Endosome ◽  
Small Gtpase ◽  
Immunogold Electron Microscopy ◽  
Cell Periphery ◽  
Early Endosomes ◽  
Cytoplasmic Vesicles ◽  
Important Site

Early endosomes in PC12 cells are an important site for the formation of synaptic-like microvesicles and constitutive recycling vesicles. By immunogold electron microscopy, the small GTPase rab4 was localized to early endosomes and numerous small vesicles in the cell periphery and Golgi area of PC12 cells. Overexpression of GTPase-deficient Q67Lrab4 increased the number of early endosome-associated and cytoplasmic vesicles, whereas expression of GDP-bound S22Nrab4 significantly increased the length of early endosomal tubules. In parallel, Q67Lrab4 induced a shift in rab4, VAMP2, and TfR label from early endosomes to peripheral vesicles, whereas S22Nrab4 increased early endosome labeling of all three proteins. These observations were corroborated by early endosome budding assays. Together, our data document a thus far unrecognized role for rab4 in the formation of synaptic-like microvesicles and add to our understanding of the formation of constitutive recycling vesicles from early endosomes.

scholarly journals A Ral GAP complex links PI 3-kinase/Akt signaling to RalA activation in insulin action

2011 ◽  
Vol 22 (1) ◽  
pp. 141-152 ◽  
Author(s):  
Xiao-Wei Chen ◽  
Dara Leto ◽  
Tingting Xiong ◽  
Genggeng Yu ◽  
Alan Cheng ◽  
...  
Keyword(s):  
Glucose Transporter ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Small Gtpase ◽  
Regulatory Subunit ◽  
Hydrolysis Of ◽  
Identification And Characterization

Insulin stimulates glucose transport in muscle  and adipose tissue by translocation of glucose transporter 4 (GLUT4) to the plasma membrane. We previously reported that activation of the small GTPase RalA downstream of PI 3-kinase plays a critical role in this process by mobilizing the exocyst complex for GLUT4 vesicle targeting in adipocytes. Here we report the identification and characterization of a Ral GAP complex (RGC) that mediates the activation of RalA downstream of the PI 3-kinase/Akt pathway. The complex is composed of an RGC1 regulatory subunit and an RGC2 catalytic subunit (previously identified as AS250) that directly stimulates the guanosine triphosphate hydrolysis of RalA. Knockdown of RGC proteins leads to increased RalA activity and glucose uptake in adipocytes. Insulin inhibits the GAP complex through Akt2-catalyzed phosphorylation of RGC2 in vitro and in vivo, while activated Akt relieves the inhibitory effect of RGC proteins on RalA activity. The RGC complex thus connects PI 3-kinase/Akt activity to the transport machineries responsible for GLUT4 translocation.

scholarly journals Small GTPase RhoG Is a Key Regulator for Neurite Outgrowth in PC12 Cells

2000 ◽  
Vol 20 (19) ◽  
pp. 7378-7387 ◽  
Author(s):  
Hironori Katoh ◽  
Hidekazu Yasui ◽  
Yoshiaki Yamaguchi ◽  
Junko Aoki ◽  
Hirotada Fujita ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Morphological Changes ◽  
Cell Types ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Wild Type ◽  
Rho Family ◽  
Constitutively Active

ABSTRACT The Rho family of small GTPases has been implicated in cytoskeletal reorganization and subsequent morphological changes in various cell types. Among them, Rac and Cdc42 have been shown to be involved in neurite outgrowth in neuronal cells. In this study, we examined the role of RhoG, another member of Rho family GTPases, in nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. Expression of wild-type RhoG in PC12 cells induced neurite outgrowth in the absence of NGF, and the morphology of wild-type RhoG-expressing cells was similar to that of NGF-differentiated cells. Constitutively active RhoG-transfected cells extended short neurites but developed large lamellipodial or filopodial structures at the tips of neurites. RhoG-induced neurite outgrowth was inhibited by coexpression with dominant-negative Rac1 or Cdc42. In addition, expression of constitutively active RhoG elevated endogenous Rac1 and Cdc42 activities. We also found that the NGF-induced neurite outgrowth was enhanced by expression of wild-type RhoG whereas expression of dominant-negative RhoG suppressed the neurite outgrowth. Furthermore, constitutively active Ras-induced neurite outgrowth was also suppressed by dominant-negative RhoG. Taken together, these results suggest that RhoG is a key regulator in NGF-induced neurite outgrowth, acting downstream of Ras and upstream of Rac1 and Cdc42 in PC12 cells.

scholarly journals Small GTPase Rin induces neurite outgrowth through Rac/Cdc42 and calmodulin in PC12 cells

2003 ◽  
Vol 163 (5) ◽  
pp. 1067-1076 ◽  
Author(s):  
Mitsunobu Hoshino ◽  
Shun Nakamura
Keyword(s):  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Binding Motif ◽  
Mutant Proteins ◽  
Neuronal Signaling ◽  
Voltage Dependent ◽  
Mitogen Activated Protein

The novel Ras-like small GTPase Rin is expressed prominently in adult neurons, and binds calmodulin (CaM) through its COOH-terminal–binding motif. It might be involved in calcium/CaM-mediated neuronal signaling, but Rin-mediated signal transduction pathways have not yet been elucidated. Here, we show that expression of Rin induces neurite outgrowth without nerve growth factor or mitogen-activated protein kinase activation in rat pheochromocytoma PC12 cells. Rin-induced neurite outgrowth was markedly inhibited by coexpression with dominant negative Rac/Cdc42 protein or CaM inhibitor treatment. We also found that expression of Rin elevated the endogenous Rac/Cdc42 activity. Rin mutant proteins, in which the mutation disrupted association with CaM, failed to induce neurite outgrowth irrespective of Rac/Cdc42 activation. Disruption of endogenous Rin function inhibited the neurite outgrowth stimulated by forskolin and extracellular calcium entry through voltage-dependent calcium channel evoked by KCl. These findings suggest that Rin-mediated neurite outgrowth signaling requires not only endogenous Rac/Cdc42 activation but also Rin–CaM association, and that endogenous Rin is involved in calcium/CaM-mediated neuronal signaling pathways.

scholarly journals MiR-133b Promotes Neurite Outgrowth by Targeting RhoA Expression

2015 ◽  
Vol 35 (1) ◽  
pp. 246-258 ◽  
Author(s):  
Xiao Cheng Lu ◽  
Jin Yu Zheng ◽  
Lin Jun Tang ◽  
Bao Sheng Huang ◽  
Kai Li ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Signaling Pathway ◽  
Pc12 Cells ◽  
Cortical Neurons ◽  
Critical Role ◽  
Axon Growth ◽  
Akt Signaling ◽  
Neural Cells ◽  
Spinal Cord Regeneration ◽  
Akt Signaling Pathway

Background: MicroRNA-133b (miR-133b) has been shown to play a critical role in spinal cord regeneration. The aim of this study was to investigate the cellular role of miR-133b in neural cells. Methods: PC12 cells and primary cortical neurons (PCNs) were transfected with lenti-miR-133b, lenti-miR-133b inhibitor, plasmid-shRNA-RhoA, plasmid-RhoA and their negative controls. After 48 hours of transfection, the levels of proteins and mRNA or miRNA were evaluated by Western blotting and qRT-PCR, respectively. Moreover, the neurite outgrowth was analyzed by Image J. For pharmacological experiments, inhibitors of MEK1/2 kinase (PD98059), phosphoinositide-3 kinase (PI3K) (LY294002) and ROCK (Y27632) were added into the culture medium. Results: Overexpression of miR-133b in PC12 cells enhanced neurite outgrowth. Conversely, inhibition of miR-133b reduced neurite length. We further identified RhoA as a target and mediator of mir-133b for neurite extension by Western blot and knockdown experiment. Moreover, overexpression of RhoA could attenuate the neurite growth effects of miR-133b. Also, we observed that miR-133b activated MEK/ERK and PI3K/Akt signaling pathway by targeting RhoA. Finally, in PCNs, miR-133b also increased axon growth and attenuated axon growth restrictions from chondroitin sulfate proteoglycans (CSPG). Conclusions: In summary, our study suggested that miR-133b regulated neurite outgrowth via ERK1/2 and PI3K/Akt signaling pathway by RhoA suppression.

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