scholarly journals ADP-Ribosylation Factor 6 Regulates Mammalian Myoblast Fusion through Phospholipase D1 and Phosphatidylinositol 4,5-Bisphosphate Signaling Pathways

2010 ◽  
Vol 21 (14) ◽  
pp. 2412-2424 ◽  
Author(s):  
Anne-Sophie Bach ◽  
Sandrine Enjalbert ◽  
Franck Comunale ◽  
Stéphane Bodin ◽  
Nicolas Vitale ◽  
...  
Keyword(s):  
Myoblast Fusion ◽  
Myoblast Differentiation ◽  
C2c12 Myoblast ◽  
Nucleotide Exchange ◽  
Adp Ribosylation ◽  
Rac1 Activity ◽  
Phospholipase D1 ◽  
Rac1 Gtpase ◽  
Gtpase Activation ◽  
Adp Ribosylation Factor

Myoblast fusion is an essential step during myoblast differentiation that remains poorly understood. M-cadherin–dependent pathways that signal through Rac1 GTPase activation via the Rho-guanine nucleotide exchange factor (GEF) Trio are important for myoblast fusion. The ADP-ribosylation factor (ARF)6 GTPase has been shown to bind to Trio and to regulate Rac1 activity. Moreover, Loner/GEP100/BRAG2, a GEF of ARF6, has been involved in mammalian and Drosophila myoblast fusion, but the specific role of ARF6 has been not fully analyzed. Here, we show that ARF6 activity is increased at the time of myoblast fusion and is required for its implementation in mouse C2C12 myoblasts. Specifically, at the onset of myoblast fusion, ARF6 is associated with the multiproteic complex that contains M-cadherin, Trio, and Rac1 and accumulates at sites of myoblast fusion. ARF6 silencing inhibits the association of Trio and Rac1 with M-cadherin. Moreover, we demonstrate that ARF6 regulates myoblast fusion through phospholipase D (PLD) activation and phosphatidylinositol 4,5-bis-phosphate production. Together, these data indicate that ARF6 is a critical regulator of C2C12 myoblast fusion and participates in the regulation of PLD activities that trigger both phospholipids production and actin cytoskeleton reorganization at fusion sites.

Growth Factors Mobilize Multiple Pools of KCa Channels in Developing Parasympathetic Neurons: Role of ADP-Ribosylation Factors and Related Proteins

2005 ◽  
Vol 94 (2) ◽  
pp. 1597-1605 ◽  
Author(s):  
Kwon-Seok Chae ◽  
Kwang-Seok Oh ◽  
Stuart E. Dryer
Keyword(s):  
Plasma Membrane ◽  
Growth Factors ◽  
Golgi Apparatus ◽  
Bound States ◽  
Brefeldin A ◽  
Dominant Negative ◽  
Over Expression ◽  
Adp Ribosylation ◽  
Phospholipase D1 ◽  
Adp Ribosylation Factor

In developing ciliary ganglion (CG) neurons, movement of functional large-conductance (BK type) Ca2+-activated K+ ( KCa) channels to the cell surface is stimulated by the endogenous growth factors TGFβ1 and β-neuregulin-1 (NRG1). Here we show that a brief NRG1 treatment (0.5–1.5 h) mobilizes KCa channels in a post-Golgi compartment, but longer treatments (>3.5 h) mobilize KCa channels located in the endoplasmic reticulum or Golgi apparatus. Specifically, the effects of 3.5 h NRG1 treatment were completely blocked by treatments that disrupt Golgi apparatus function. These include inhibition of microtubules, or inhibition of the ADP-ribosylation factor-1 (ARF1) system by brefeldin A, by over-expression of dominant-negative ARF1, or over-expression of an ARF1 GTPase-activating protein that blocks ARF1 cycling between GTP- and GDP-bound states. These treatments had no effect on stimulation of KCa evoked by 1.5 h treatment with NRG1, indicating that short-term responses to NRG1 do not require an intact Golgi apparatus. By contrast, both the acute and sustained effects of NRG1 were inhibited by treatments that block trafficking processes that occur close to the plasma membrane. Thus mobilization of KCa was blocked by treatments than inhibit ADP-ribosylation factor-6 (ARF6) signaling, including overexpression of dominant-negative ARF6, dominant-negative ARNO, or dominant-negative phospholipase D1. TGFβ1, the effects of which on KCa are much slower in onset, is unable to selectively mobilize channels in the post-Golgi pool, and its effects on KCa are completely blocked by inhibition of microtubules, Golgi function and also by plasma membrane ARF6 and phospholipase D1 signaling.

scholarly journals Confocal imaging of the subcellular distribution of phosphatidylinositol 3,4,5-trisphosphate in insulin- and PDGF-stimulated 3T3-L1 adipocytes

1999 ◽  
Vol 344 (2) ◽  
pp. 511-518 ◽  
Author(s):  
Paru B. OATEY ◽  
Kanamarlapudi VENKATESWARLU ◽  
Alan G. WILLIAMS ◽  
Laura M. FLETCHER ◽  
Emily J. FOULSTONE ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Subcellular Localization ◽  
Glucose Uptake ◽  
Confocal Imaging ◽  
Glut4 Translocation ◽  
Nucleotide Exchange ◽  
Subcellular Targeting ◽  
Adp Ribosylation ◽  
Nucleotide Exchange Factors ◽  
Adp Ribosylation Factor

The activation of phosphatidylinositol 3-kinase (PI 3-kinase) and production of PtdIns(3,4,5)P3 is crucial in the actions of numerous extracellular stimuli, including insulin-stimulated glucose uptake. Platelet-derived growth factor (PDGF) also stimulates PI 3-kinase, but only weakly promotes glucose uptake when compared with insulin. Insulin and PDGF have thus been proposed to have differential effects on the subcellular targeting of PI 3-kinase. However, owing to a lack of suitable methodologies, the subcellular localization of the PtdIns(3,4,5)P3 generated has not been examined. The pleckstrin-homology (PH) domains of the nucleotide exchange factors, ADP-ribosylation factor nucleotide-binding-site opener (ARNO) and general receptor for 3-phosphoinositides (GRP1), which have a high affinity and specificity for PtdIns(3,4,5)P3, were fused to green fluorescent protein and used to examine the subcellular localization of PtdIns(3,4,5)P3 generation in living 3T3-L1 adipocytes. PtdIns(3,4,5)P3 was produced almost exclusively in the plasma membrane in response to both agonists, although the response to insulin was greater in magnitude and occurred in considerably more cells. The results suggest that the greater ability of insulin to stimulate glucose uptake may be the result of its ability to generate significantly more plasma-membrane PtdIns(3,4,5)P3 than PDGF. ARNO and GRP1 are nucleotide exchange factors for the small GTP-binding protein ADP-ribosylation factor 6 (ARF6). The inability of a constitutively active GTPase-deficient mutant of ARF6 (ARF6-Q67L; Gln67 → Leu) to cause glucose transporter GLUT4 translocation suggests that activation of this pathway is not sufficient to cause GLUT4 translocation.

scholarly journals Asef controls vascular endothelial permeability and barrier recovery in the lung

2015 ◽  
Vol 26 (4) ◽  
pp. 636-650 ◽  
Author(s):  
Xinyong Tian ◽  
Yufeng Tian ◽  
Grzegorz Gawlak ◽  
Fanyong Meng ◽  
Yoshihiro Kawasaki ◽  
...  
Keyword(s):  
Lung Injury ◽  
Endothelial Permeability ◽  
Dominant Negative ◽  
Nucleotide Exchange ◽  
Protective Mechanisms ◽  
Compensatory Response ◽  
Cytoskeletal Dynamics ◽  
Rac1 Gtpase ◽  
Gtpase Activation

Increased levels of hepatocyte growth factor (HGF) in injured lungs may reflect a compensatory response to diminish acute lung injury (ALI). HGF-induced activation of Rac1 GTPase stimulates endothelial barrier protective mechanisms. This study tested the involvement of Rac-specific guanine nucleotide exchange factor Asef in HGF-induced endothelial cell (EC) cytoskeletal dynamics and barrier protection in vitro and in a two-hit model of ALI. HGF induced membrane translocation of Asef and stimulated Asef Rac1-specific nucleotide exchange activity. Expression of constitutively activated Asef mutant mimicked HGF-induced peripheral actin cytoskeleton enhancement. In contrast, siRNA-induced Asef knockdown or expression of dominant-negative Asef attenuated HGF-induced Rac1 activation evaluated by Rac-GTP pull down and FRET assay with Rac1 biosensor. Molecular inhibition of Asef attenuated HGF-induced peripheral accumulation of cortactin, formation of lamellipodia-like structures, and enhancement of VE-cadherin adherens junctions and compromised HGF-protective effect against thrombin-induced RhoA GTPase activation, Rho-dependent cytoskeleton remodeling, and EC permeability. Intravenous HGF injection attenuated lung inflammation and vascular leak in the two-hit model of ALI induced by excessive mechanical ventilation and thrombin signaling peptide TRAP6. This effect was lost in Asef− /− mice. This study shows for the first time the role of Asef in HGF-mediated protection against endothelial hyperpermeability and lung injury.

scholarly journals Colocalization of phospholipase D1 and GTP-binding-defective mutant of ADP-ribosylation factor 6 to endosomes and lysosomes

FEBS Letters ◽  
1999 ◽  
Vol 442 (2-3) ◽  
pp. 221-225 ◽  
Author(s):  
Kyoko Toda ◽  
Masahiro Nogami ◽  
Kazuo Murakami ◽  
Yasunori Kanaho ◽  
Kazuhisa Nakayama
Keyword(s):  
Adp Ribosylation ◽  
Gtp Binding ◽  
Defective Mutant ◽  
Phospholipase D1 ◽  
Adp Ribosylation Factor

scholarly journals Regulation of GRP1-catalyzed ADP Ribosylation Factor Guanine Nucleotide Exchange by Phosphatidylinositol 3,4,5-Trisphosphate

1998 ◽  
Vol 273 (4) ◽  
pp. 1859-1862 ◽  
Author(s):  
Jes K. Klarlund ◽  
Lucia E. Rameh ◽  
Lewis C. Cantley ◽  
Joanne M. Buxton ◽  
John J. Holik ◽  
...  
Keyword(s):  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Adp Ribosylation ◽  
Guanine Nucleotide Exchange ◽  
Adp Ribosylation Factor

scholarly journals ADP-ribosylation factor (ARF)-like 4, 6, and 7 represent a subgroup of the ARF family characterized by rapid nucleotide exchange and a nuclear localization signal

FEBS Letters ◽  
1999 ◽  
Vol 456 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Stephan Jacobs ◽  
Christiane Schilf ◽  
Frank Fliegert ◽  
Susanne Koling ◽  
Yvonne Weber ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nucleotide Exchange ◽  
Adp Ribosylation ◽  
Localization Signal ◽  
Adp Ribosylation Factor
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