Membrane Traffic: Exocyst III – Makes a Family

Short, Ben; Barr, Francis A.

doi:10.1016/s0960-9822(01)00641-8

Cited by 14 publications

(7 citation statements)

References 20 publications

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“…Recently, Rac and also Rho, Cdc42, Ral, and PLD1 have been shown to participate in a multiprotein complex that comprises Sec6/Sec 8 proteins, termed "exocyst" (Brymora et al, 2001;Guo et al, 2001;Moskalenko et al, 2002;Short and Barr, 2002), which is present in nerve terminals and growth cones (Hazuka et al, 1999;Brymora et al, 2001;Vega and Hsu, 2001). The exocyst is believed to regulate polarized secretion and docking of vesicles to regions of the plasma membrane specialized in exocytosis, possibly in a one-to-one stoichiometry with fusion sites (for review, see Short and Barr, 2002). Therefore, inactivation of Rac in the exocyst might be responsible for disrupting the supply of SV to release sites in an all-or-none manner.…”

Section: How Can Rac Glucosylation Cause Reduction In the Number Of Amentioning

confidence: 99%

Rac GTPase Plays an Essential Role in Exocytosis by Controlling the Fusion Competence of Release Sites

et al. 2002

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The role of small GTPases of the Rho family in synaptic functions has been addressed by analyzing the effects of lethal toxin (LT) from Clostridium sordellii strain IP82 (LT82) on neurotransmitter release at evoked identified synapses in the buccal ganglion of Aplysia. LT82 is a large monoglucosyltranferase that uses UDP-glucose as cofactor and glucosylates Rac (a small GTPase related to Rho), and Ras, Ral, and Rap (three GTPases of the Ras family). Intraneuronal application of LT (50 nm) rapidly inhibits evoked acetylcholine (ACh) release as monitored electrophysiologically. Injection of the catalytic domain of the toxin similarly blocked ACh release, but not when key amino acids needed for glucosylation were mutated. Intraneuronal application of competitive nucleotide sugars that differentially prevent glucosylation of Rac- and Ras-related GTPases, and the use of a toxin variant that affects a different spectrum of small GTPases, established that glucosylation of Rac is responsible for the reduction in ACh release. To determine the quantal release parameters affected by Rac glucosylation, we developed a nonstationary analysis of the fluctuations in postsynaptic response amplitudes that was performed before and after the toxin had acted or during toxin action. The results indicate that neither the quantal size nor the average probability for release were affected by lethal toxin action. ACh release blockage by LT82 was only caused by a reduction in the number of functional release sites. This reveals that after docking of synaptic vesicles, vesicular Rac stimulates a membrane effector (or effectors) essential for the fusion competence of the exocytotic sites.

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Section: How Can Rac Glucosylation Cause Reduction In the Number Of Amentioning

confidence: 99%

Rac GTPase Plays an Essential Role in Exocytosis by Controlling the Fusion Competence of Release Sites

et al. 2002

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“…What is the role of Rac during priming? Rac, Rho, Cdc42, Ral, and PLD1 all participate in a multiprotein complex termed “exocyst,” which is comprised of Sec6/Sec8 proteins and regulates polarized secretion as well as docking of vesicles to plasma membrane regions specialized in exocytosis [271]. Therefore, one cannot exclude that Rho-acting toxins block exocytosis by disabling exocyst function in nerve endings.…”

Section: Toxins Inhibiting the Neuroexocytosismentioning

confidence: 99%

Bacterial Toxins and the Nervous System: Neurotoxins and Multipotential Toxins Interacting with Neuronal Cells

Popoff

Poulain

2010

Toxins

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Toxins are potent molecules used by various bacteria to interact with a host organism. Some of them specifically act on neuronal cells (clostridial neurotoxins) leading to characteristics neurological affections. But many other toxins are multifunctional and recognize a wider range of cell types including neuronal cells. Various enterotoxins interact with the enteric nervous system, for example by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, in amplification of the diarrhea, or in intestinal inflammation process. Other toxins can pass the blood brain barrier and directly act on specific neurons.

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“…p115 was shown to participate in the stacking of p97-generated cisternae in an in vitro assay . Furthermore, GRASP55 has been shown to interact with Golgin-45 (Short and Barr 2002), possibly forming a second complex involved in stacking.…”

Section: Golgi Stackingmentioning

confidence: 99%

Golgi apparatus partitioning during cell division (Review)

Rabouille

Jokitalo

2003

Molecular Membrane Biology

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This review discusses the mitotic segregation of the Golgi apparatus. The results from classical biochemical and morphological studies have suggested that in mammalian cells this organelle remains distinct during mitosis, although highly fragmented through the formation of mitotic Golgi clusters of small tubules and vesicles. Shedding of free Golgi-derived vesicles would consume Golgi clusters and disperse this organelle throughout the cytoplasm. Vesicles could be partitioned in a stochastic and passive way between the two daughter cells and act as a template for the reassembly of this key organelle. This model has recently been modified by results obtained using GFP- or HRP-tagged Golgi resident enzymes, live cell imaging and electron microscopy. Results obtained with these techniques show that the mitotic Golgi clusters are stable entities throughout mitosis that partition in a microtubule spindle-dependent fashion. Furthermore, a newer model proposes that at the onset of mitosis, the Golgi apparatus completely loses its identity and is reabsorbed into the endoplasmic reticulum. This suggests that the partitioning of the Golgi apparatus is entirely dependent on the partitioning of the endoplasmic reticulum. We critically discuss both models and summarize what is known about the molecular mechanisms underlying the Golgi disassembly and reassembly during and after mitosis. We will also review how the study of the Golgi apparatus during mitosis in other organisms can answer current questions and perhaps reveal novel mechanisms.

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Membrane Traffic: Exocyst III – Makes a Family

Cited by 14 publications

References 20 publications

Rac GTPase Plays an Essential Role in Exocytosis by Controlling the Fusion Competence of Release Sites

Rac GTPase Plays an Essential Role in Exocytosis by Controlling the Fusion Competence of Release Sites

Bacterial Toxins and the Nervous System: Neurotoxins and Multipotential Toxins Interacting with Neuronal Cells

Golgi apparatus partitioning during cell division (Review)

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