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 Identification of centaurin-α1 as a potential in vivo phosphatidylinositol 3,4,5-trisphosphate-binding protein that is functionally homologous to the yeast ADP-ribosylation factor (ARF) GTPase-activating protein, Gcs1

1999 ◽  
Vol 340 (2) ◽  
pp. 359-363 ◽  
Author(s):  
Kanamarlapudi VENKATESWARLU ◽  
Paru B. OATEY ◽  
Jeremy M. TAVARÉ ◽  
Trevor R. JACKSON ◽  
Peter J. CULLEN
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Fluorescent Protein ◽  
Binding Protein ◽  
Dominant Negative ◽  
Gtpase Activating Protein ◽  
Adp Ribosylation ◽  
Adp Ribosylation Factor

Centaurin-α is a 46 kDa in vitro binding protein for the lipid second messenger PtdIns(3,4,5)P3. In this report we have addressed whether centaurin-α1, a human homologue of centaurin-α, binds PtdIns(3,4,5)P3in vivo and furthermore, identified a potential physiological function for centaurin-α1. Using confocal microscopy of live PC12 cells, transiently transfected with a chimera of green fluorescent protein (GFP) fused to the N-terminus of centaurin-α1 (GFP-centaurin-α1), we demonstrated the rapid plasma membrane recruitment of cytosolic GFP-centaurin-α1 following stimulation with either nerve growth factor or epidermal growth factor. This recruitment was dependent on the centaurin-α1 pleckstrin homology domains and was blocked by the PtdIns(4,5)P2 3-kinase (PI 3-kinase) inhibitors wortmannin (100 nM) and LY294002 (50 μM), and also by co-expression with a dominant negative p85. Functionally, we demonstrated that centaurin-α1 could complement a yeast strain deficient in the ADP-ribosylation factor (ARF) GTPase-activating protein Gcs1; a complementation that was blocked by mutagenesis of conserved cysteine residues within the ARF GTPase-activating protein analogous domain of centaurin-α1. Taken together, our data demonstrated that centaurin-α1 could potentially function as an ARF GTPase-activating protein that, on agonist stimulation, was recruited to the plasma membrane possibly through an ability to interact with PtdIns(3,4,5)P3.

scholarly journals ADP Ribosylation Factor 1 Is Required for Synaptic Vesicle Budding in PC12 Cells

1997 ◽  
Vol 138 (3) ◽  
pp. 505-515 ◽  
Author(s):  
Victor Faúndez ◽  
Jim-Tong Horng ◽  
Regis B. Kelly
Keyword(s):  
Pc12 Cell ◽  
Cell Membranes ◽  
Brefeldin A ◽  
T Antigen ◽  
Gtpase Activity ◽  
Vesicle Budding ◽  
Adp Ribosylation ◽  
Adp Ribosylation Factor

Carrier vesicle generation from donor membranes typically progresses through a GTP-dependent recruitment of coats to membranes. Here we explore the role of ADP ribosylation factor (ARF) 1, one of the GTP-binding proteins that recruit coats, in the production of neuroendocrine synaptic vesicles (SVs) from PC12 cell membranes. Brefeldin A (BFA) strongly and reversibly inhibited SV formation in vivo in three different PC12 cell lines expressing vesicle-associated membrane protein–T Antigen derivatives. Other membrane traffic events remained unaffected by the drug, and the BFA effects were not mimicked by drugs known to interfere with formation of other classes of vesicles. The involvement of ARF proteins in the budding of SVs was addressed in a cell-free reconstitution system (Desnos, C., L. Clift-O'Grady, and R.B. Kelly. 1995. J. Cell Biol. 130:1041–1049). A peptide spanning the effector domain of human ARF1 (2–17) and recombinant ARF1 mutated in its GTPase activity, both inhibited the formation of SVs of the correct size. During in vitro incubation in the presence of the mutant ARFs, the labeled precursor membranes acquired different densities, suggesting that the two ARF mutations block at different biosynthetic steps. Cell-free SV formation in the presence of a high molecular weight, ARF-depleted fraction from brain cytosol was significantly enhanced by the addition of recombinant myristoylated native ARF1. Thus, the generation of SVs from PC12 cell membranes requires ARF and uses its GTPase activity, probably to regulate coating phenomena.

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 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.

scholarly journals ADP ribosylation factor 6 is activated and controls membrane delivery during phagocytosis in macrophages

2003 ◽  
Vol 161 (6) ◽  
pp. 1143-1150 ◽  
Author(s):  
Florence Niedergang ◽  
Emma Colucci-Guyon ◽  
Thierry Dubois ◽  
Graça Raposo ◽  
Philippe Chavrier
Keyword(s):  
Actin Polymerization ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Adp Ribosylation ◽  
Transient Activation ◽  
Endosomal Recycling ◽  
Membrane Protrusions ◽  
Specific Receptors ◽  
Intracellular Vesicles ◽  
Adp Ribosylation Factor

Engulfment of particles by phagocytes is induced by their interaction with specific receptors on the cell surface, which leads to actin polymerization and the extension of membrane protrusions to form a closed phagosome. Membrane delivery from internal pools is considered to play an important role in pseudopod extension during phagocytosis. Here, we report that endogenous ADP ribosylation factor 6 (ARF6), a small GTP-binding protein, undergoes a sharp and transient activation in macrophages when phagocytosis was initiated via receptors for the Fc portion of immunoglobulins (FcRs). A dominant-negative mutant of ARF6 (T27N mutation) dramatically affected FcR-mediated phagocytosis. Expression of ARF6-T27N lead to a reduction in the focal delivery of vesicle-associated membrane protein 3+ endosomal recycling membranes at phagocytosis sites, whereas actin polymerization was unimpaired. This resulted in an early blockade in pseudopod extension and accumulation of intracellular vesicles, as observed by electron microscopy. We conclude that ARF6 is a major regulator of membrane recycling during phagocytosis.

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