Clostridium Botulinum C3 Exoenzyme Stimulates GLUT4-Mediated Glucose Transport, but Not Glycogen Synthesis, in 3T3-L1 Adipocytes—A Potential Role of rho?

Berghe, N. Van Den; Barros, L. Felipe; Mackelenbergh, M. G. H. Van; Krans, H. M. J.

doi:10.1006/bbrc.1996.1821

Cited by 14 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Isolated plasma membrane lawns from 3T3‐L1 adipocytes were prepared and quantified as described previously (van den Berghe, Barros, van Mackelenbergh & Krans, 1996). By varying the gain of the confocal detection system, it was verified that under the conditions used, a linear relationship existed between the fluorescence detected and the amplitude of the signal as quantified using the imaging system.…”

Section: Methodsmentioning

confidence: 99%

Evidence of two mechanisms for the activation of the glucose transporter GLUT1 by anisomycin: p38(MAP kinase) activation and protein synthesis inhibition in mammalian cells

Barros

Young²,

Saklatvala³

et al. 1997

The Journal of Physiology

View full text Add to dashboard Cite

Inhibitors of protein synthesis stimulate sugar transport in mammalian cells through activation of plasma membrane GLUT1, the housekeeping isoform of the glucose transporter. However, it has been reported that some of these compounds, in addition to their effect on protein synthesis, also activate protein kinases. In the present study we have explored the role of these two effects on GLUT1 activation. In 3T3‐L1 adipocytes and Clone 9 cells, stimulation of sugar transport by puromycin, a translational inhibitor that does not activate kinases, was not detectable until 90 min after exposure. In contrast, stimulation by anisomycin, a potent Jun‐NH2‐terminal kinase (JNK) agonist, exhibited no lag phase. An intermediate response was observed to emetine and cycloheximide, weak activators of JNK. The potency of anisomycin to stimulate transport acutely (30 min of exposure) was 5‐ to 10‐fold greater than for its chronic stimulation of transport, measured after 4 h of exposure. The stimulation of transport by a low concentration of anisomycin (0.3 μm) was transient, peaked at 30–60 min and it was inhibited (IC50 < 1 μm) by SB203580, which indicates that its mediator is not JNK, but the homologous p38(MAP kinase) (p38(MAPK)). In contrast, the responses to 4 h exposure to 300 μm anisomycin or puromycin were refractory to SB203580. Exposure to anisomycin resulted in rapid activation of p38(MAPK). Activation of both p38(MAPK) and GLUT1 by 0.3 μm anisomycin was cancelled by puromycin. We conclude that the activation of GLUT1 in response to anisomycin includes two components: a delayed component involving translational inhibition and a fast, puromycin‐inhibitable component that is secondary to activation of p38(MAPK).

show abstract

Section: Methodsmentioning

confidence: 99%

Evidence of two mechanisms for the activation of the glucose transporter GLUT1 by anisomycin: p38(MAP kinase) activation and protein synthesis inhibition in mammalian cells

Barros

Young²,

Saklatvala³

et al. 1997

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

Hyperosmotic shock induces both activation and translocation of glucose transporters in mammalian cells

Barros

Barnes

Ingram

et al. 2001

Pfl�gers Archiv European Journal of Physiology

View full text Add to dashboard Cite

The effect of osmotic stress on sugar transport was investigated in Clone 9 epithelial cells, which express the glucose uniporter GLUT1, and in 3T3-L1 adipocytes, which express both GLUT1 and GLUT4. An acute hyperosmotic shock increased the uptake of sugars in both cell types. In Clone 9 cells, this was followed by a regulatory volume increase (RVI) response. Stimulation of transport was rapid and reversible, with half-lives (t 1/2) for stimulation of 2-deoxy-D-glucose uptake of 5.6 +/- 0.9 (n=6) and 22.7 +/- 1.5 (n=4) min for Clone 9 cells and adipocytes respectively. The effect was dose dependent, reaching a maximum at 1.1 osM of 2.9 +/- 0.1-fold (n=3) for Clone 9 cells and 8.2 +/- 0.8-fold (n=3) for adipocytes. In the latter, this stimulation correlated with translocation of the glucose transporter isoform GLUT4 to the cell surface and was not significantly different from that elicited by 160 nM insulin (7.6 +/- 1.2-fold, n=3). The effect of osmotic shock was not, however, influenced by inhibitors of either phosphoinositide 3-kinase (PI 3-kinase) (wortmannin, 250 nM) or of p38 mitogen-activated protein kinase (p38 MAP kinase) (SB203580, 20 microM), which reportedly prevent GLUT4 translocation and/or activation by insulin respectively. These inhibitors also had no effect on the stimulation of transport by osmotic shock in Clone 9 cells. However, in contrast to adipocytes, the effect of osmotic shock on glucose transport in Clone 9 cells reflected primarily a change in the intrinsic activity of cell surface transporters and there was only a minor change in their subcellular distribution as assessed by cell immunostaining or no change as assessed by surface biotinylation. These results indicate that the response of cells to osmotic shock can involve changes both in transporter activity and location. The signal transduction pathways involved include neither PI 3-kinase nor the classical, osmotically-activated component, p38 MAP kinase.

show abstract

Activation of Store-Operated Ca2+ Current in Xenopus Oocytes Requires SNAP-25 but Not a Diffusible Messenger

Yao

Ferrer‐Montiel

Montal

et al. 1999

Cell

250

185

View full text Add to dashboard Cite

Depletion of Ca2+ stores in Xenopus oocytes activated entry of Ca2+ across the plasma membrane, which was measured as a current I(soc) in subsequently formed cell-attached patches. I(soc) survived excision into inside-out configuration. If cell-attached patches were formed before store depletion, I(soc) was activated outside but not inside the patches. I(soc) was potentiated by microinjection of Clostridium C3 transferase, which inhibits Rho GTPase, whereas I(soc) was inhibited by expression of wild-type or constitutively active Rho. Activation of I(soc) was also inhibited by botulinum neurotoxin A and dominant-negative mutants of SNAP-25 but was unaffected by brefeldin A. These results suggest that oocyte I(soc) is dependent not on aqueous diffusible messengers but on SNAP-25, probably via exocytosis of membrane channels or regulatory molecules.

show abstract

Clostridium Botulinum C3 Exoenzyme Stimulates GLUT4-Mediated Glucose Transport, but Not Glycogen Synthesis, in 3T3-L1 Adipocytes—A Potential Role of rho?

Cited by 14 publications

References 0 publications

Evidence of two mechanisms for the activation of the glucose transporter GLUT1 by anisomycin: p38(MAP kinase) activation and protein synthesis inhibition in mammalian cells

Evidence of two mechanisms for the activation of the glucose transporter GLUT1 by anisomycin: p38(MAP kinase) activation and protein synthesis inhibition in mammalian cells

Hyperosmotic shock induces both activation and translocation of glucose transporters in mammalian cells

Activation of Store-Operated Ca2+ Current in Xenopus Oocytes Requires SNAP-25 but Not a Diffusible Messenger

Contact Info

Product

Resources

About