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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have recently described a system that recreates in vitro the generation of post-Golgi vesicles from purified Golgi fractions obtained from virus-infected MDCK cells in which the vesicular stomatitis virus-G envelope glycoprotein had been allowed to accumulate in vivo in the TGN. Vesicle formation, monitored by the release of the viral glycoprotein, was shown to require the activation of a GTP-binding ADP ribosylation factor (ARF) protein that promotes the assembly of a vesicle coat in the TGN, and to be regulated by a Golgi-associated protein kinase C (PKC)-like activity. We have now been able to dissect the process of post-Golgi vesicle generation into two sequential stages, one of coat assembly and bud formation, and another of vesicle scission, neither of which requires an ATP supply. The first stage can occur at 20 degrees C, and includes the GTP-dependent activation of the ARF protein, which can be effected by the nonhydrolyzable nucleotide analogue GTP gamma S, whereas the second stage is nucleotide independent and can only occur at a higher temperature of incubation. Cytosolic proteins are required for the vesicle scission step and they cannot be replaced by palmitoyl CoA, which is known to promote, by itself, scission of the coatomer-coated vesicles that mediate intra-Golgi transport. We have found that PKC inhibitors prevented vesicle generation, even when this was sustained by GTP gamma S and ATP levels reduced far below the K(m) of PKC. The inhibitors suppressed vesicle scission without preventing coat assembly, yet to exert their effect, they had to be added before coat assembly took place. This indicates that a target of the putative PKC is activated during the bud assembly stage of vesicle formation, but only acts during the phase of vesicle release. The behavior of the PKC target during vesicle formation resembles that of phospholipase D (PLD), a Golgi-associated enzyme that has been shown to be activated by PKC, even in the absence of the latter's phosphorylating activity. We therefore propose that during coat assembly, PKC activates a PLD that, during the incubation at 37 degrees C, promotes vesicle scission by remodeling the phospholipid bilayer and severing connections between the vesicles and the donor membrane.
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PMID:The production of post-Golgi vesicles requires a protein kinase C-like molecule, but not its phosphorylating activity. 889 94

Homologues of two major components of the well-characterized erythrocyte plasma-membrane-skeleton, spectrin (a not-yet-cloned isoform, betaI Sigma* spectrin) and ankyrin (AnkG119 and an approximately 195-kDa ankyrin), associate with the Golgi complex. ADP ribosylation factor (ARF) is a small G protein that controls the architecture and dynamics of the Golgi by mechanisms that remain incompletely understood. We find that activated ARF stimulates the in vitro association of betaI Sigma* spectrin with a Golgi fraction, that the Golgi-associated betaI Sigma* spectrin contains epitopes characteristic of the betaI Sigma2 spectrin pleckstrin homology (PH) domain known to bind phosphatidylinositol 4,5-bisphosphate (PtdInsP2), and that ARF recruits betaI Sigma* spectrin by inducing increased PtdInsP2 levels in the Golgi. The stimulation of spectrin binding by ARF is independent of its ability to stimulate phospholipase D or to recruit coat proteins (COP)-I and can be blocked by agents that sequester PtdInsP2. We postulate that a PH domain within betaI Sigma* Golgi spectrin binds PtdInsP2 and acts as a regulated docking site for spectrin on the Golgi. Agents that block the binding of spectrin to the Golgi, either by blocking the PH domain interaction or a constitutive Golgi binding site within spectrin's membrane association domain I, inhibit the transport of vesicular stomatitis virus G protein from endoplasmic reticulum to the medial compartment of the Golgi complex. Collectively, these results suggest that the Golgi-spectrin skeleton plays a central role in regulating the structure and function of this organelle.
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PMID:ADP ribosylation factor regulates spectrin binding to the Golgi complex. 967 25

Class I ADP-ribosylation factors (ARFs) are essential for coatomer and clathrin coat assembly and vesicular transport in the Golgi apparatus. However, little is known about the in vivo regulation of ARF actions. Recently we cloned arfaptin 1, a 39 kDa protein that binds active, GTPgammaS-liganded ARF and translocates with it to Golgi membranes. Here we show that phorbol ester-stimulated phospholipase D (PLD) activity is inhibited in arfaptin 1-overexpressing NIH 3T3 cells and that arfaptin 1 inhibits ARF activation of Golgi-associated PLD. Since PLD activity is thought to play a role in regulating vesicular transport in the secretory pathway, we determined the rate of glycosylation of vesicular stomatitis virus glycoprotein as a measure of protein transport from the endoplasmic reticulum through the Golgi apparatus. Arfaptin 1 overexpression was found to decrease the rate of this reaction approximately two-fold. These data suggest that arfaptin 1 is a regulator of ARF action in the Golgi apparatus.
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PMID:Arfaptin 1, an ARF-binding protein, inhibits phospholipase D and endoplasmic reticulum/Golgi protein transport. 998 4

Intracellular mature vaccinia virions are wrapped by cisternae, derived from virus-modified trans-Golgi or endosomal membranes, and then transported via microtubules to the cell periphery. Two viral proteins, encoded by the F13L and B5R open reading frames, are essential for the membrane-wrapping step. Previous transfection studies indicated that F13L induces the formation of post-Golgi vesicles that incorporate the B5R protein and that this activity depends on an intact F13L phospholipase motif. Here we show that the F13L protein has a general effect on the trafficking of integral membrane proteins from the Golgi apparatus, as both the vaccinia virus A36R protein and the vesicular stomatitis virus G protein also colocalized with the F13L protein in vesicles. In addition, increased expression of cellular phospholipase D, which has a similar phospholipase motif as, but little amino acid sequence identity with, F13L, induced post-Golgi vesicles that contained B5R and A36R proteins. Butanol-1, which prevents the formation of phosphatidic acid by phospholipase D and specifically inhibits phospholipase D-mediated vesicle formation, also inhibited F13L-induced vesicle formation, whereas secondary and tertiary alcohols had no effect. Moreover, inhibition of phospholipase activity by butanol-1 also reduced plaque size and decreased the formation of extracellular vaccinia virus without affecting the yield of intracellular mature virus. Phospholipase D, however, could not complement a vaccinia virus F13L deletion mutant, indicating that F13L has additional virus-specific properties. Taken together, these data support an important role for F13L in inducing the formation of vesicle precursors of the vaccinia virus membrane via phospholipase activity or activation.
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PMID:Similarities in the induction of post-Golgi vesicles by the vaccinia virus F13L protein and phospholipase D. 1209 90