Action of Pasteurella multocida toxin on Gαq is persistent and independent of interaction with G-protein-coupled receptors

Orth, J.; Lang, Simona; Preuß, Inga; Milligan, Graeme; Aktories, Klaus

doi:10.1016/j.cellsig.2007.06.016

Cited by 20 publications

(25 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, we found that both receptor-dependent and forskolin-mediated stimulation of adenylyl cyclase activity in membrane preparations of fibroblasts were inhibited by pretreatment with PMT. These findings indicated that PMT causes activation of G i , which is in line with recent findings that the effects of PMT are persistent in membrane preparations of toxin-pretreated cells (26).…”

Section: Discussionsupporting

confidence: 81%

“…Incubation of fibroblasts with PMT, followed by stimulation with the ␤-adrenoreceptor agonist isoproterenol or with the adenylyl cyclase activator forskolin, leads to dose-dependent inhibition of both receptor-dependent (isoproterenol) and receptor-independent (forskolin) cAMP accumulation. The EC 50 values for PMT were in the same range as reported previously for the stimulation of the G q -PLC␤ pathway by the toxin (26). The inhibitory effects of PMT on cAMP accumulation were not observed with the inactive PMT C1165S mutant.…”

Section: Discussionsupporting

confidence: 69%

“…After centrifugation at 200 ϫ g for 5 min at 4°C, the resulting supernatant was centrifuged at 20,000 ϫ g for 30 min. The resulting membrane pellet was resuspended in TE buffer (26).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Activation of Gαi and Subsequent Uncoupling of Receptor-Gαi Signaling by Pasteurella multocida Toxin

Orth

Fester

Preuß

et al. 2008

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Bacterial protein toxins are powerful tools for elucidating signaling mechanisms in eukaryotic cells. A number of bacterial protein toxins, e.g. cholera toxin, pertussis toxin (PTx), or Pasteurella multocida toxin (PMT), target heterotrimeric G proteins and have been used to stimulate or block specific signaling pathways or to demonstrate the contribution of their target proteins in cellular effects. PMT is a major virulence factor of P. multocida causing pasteurellosis in man and animals and is responsible for atrophic rhinitis in pigs. PMT modulates various signaling pathways, including phospholipase C␤ and RhoA, by acting on the heterotrimeric G proteins G␣ q and G␣ 12/13 , respectively. Here we report that PMT is a powerful activator of G i protein. We show that PMT decreases basal isoproterenol and forskolin-stimulated cAMP accumulation in intact Swiss 3T3 cells, inhibits adenylyl cyclase activity in cell membrane preparations, and enhances the inhibition of cAMP accumulation caused by lysophosphatidic acid via endothelial differentiation gene receptors. PMT-mediated inhibition of cAMP production is independent of toxin activation of G␣ q and/or G␣ 12/13 . Although the effects of PMT are not inhibited by PTx, PMT blocks PTx-catalyzed ADP-ribosylation of G i . PMT also inhibits steadystate GTPase activity and GTP binding of G i in Swiss 3T3 cell membranes stimulated by lysophosphatidic acid. The data indicate that PMT is a novel activator of G i , modulating its GTPase activity and converting it into a PTx-insensitive state.

show abstract

Section: Discussionsupporting

confidence: 81%

Section: Discussionsupporting

confidence: 69%

See 1 more Smart Citation

Activation of Gαi and Subsequent Uncoupling of Receptor-Gαi Signaling by Pasteurella multocida Toxin

Orth

Fester

Preuß

et al. 2008

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…Furthermore, deamidation of glutamine-205 of G␣ i2 by PMT plausibly explains why PMT prevents the ADP-ribosylation of the G protein by PTx and results in inhibition of basal and RGS-stimulated GTPase activity. Moreover, the deamidase function of PMT is in line with the report of GPCR-independent activation of G␣ q by the toxin (27). So far we were not able to detect a PMT-catalyzed deamidase activity of G proteins in membrane preparations of mammalian cells or with recombinant G proteins, when the toxin was added after preparing the cell membranes or after expression and isolation of the G protein.…”

Section: Discussionsupporting

confidence: 68%

Pasteurella multocida toxin activation of heterotrimeric G proteins by deamidation

Orth

Preuß

Fester

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

103

123

View full text Add to dashboard Cite

Pasteurella multocida toxin is a major virulence factor of Pasteurella multocida, which causes pasteurellosis in men and animals and atrophic rhinitis in rabbits and pigs. The Ϸ145 kDa protein toxin stimulates various signal transduction pathways by activating heterotrimeric G proteins of the G␣ q, G␣i, and G␣12/13 families by using an as yet unknown mechanism. Here, we show that Pasteurella multocida toxin deamidates glutamine-205 of G␣ i2 to glutamic acid. Therefore, the toxin inhibits the intrinsic GTPase activity of G␣ i and causes persistent activation of the G protein. A similar modification is also evident for G␣ q, but not for the closely related G␣ 11, which is not a substrate of Pasteurella multocida toxin. Our data identify the ␣-subunits of heterotrimeric G proteins as the direct molecular target of Pasteurella multocida toxin and indicate that the toxin does not act like a protease, which was suggested from its thiol protease-like catalytic triad, but instead causes constitutive activation of G proteins by deamidase activity.bacterial protein toxin ͉ Gi protein ͉ posttranslational modification ͉ transglutaminase

show abstract

“…PMT is a glutamine-specific protein deamidase; it acts by deamidation of specific glutamine residues in the a-subunit of heterotrimeric G proteins that inhibit GTPase activity in a way that stimulates a large subset of signal transduction pathways. In the end, PMT upregulates JAK (Janus kinase) and STAT 1,3,5 (signal transducers of transcription) to activate Gaq, which leads to rise in intracellular Ca 2þ , accumulation of inositol phosphates, and activation of phospholipase C (Orth et al 2007). In hepatocytes, PMT enters the cell into late endosomes, by receptor mediated endocytosis-sharing a receptor pathway with transferrin and cholera toxin (Repella et al 2011).…”

Section: Ca 2þ Import: Plasma Membrane To Ser To Mitochondriamentioning

confidence: 99%

Ultrastructural Pathology and Interorganelle Cross Talk in Hepatotoxicity

Cheville

2013

Toxicol Pathol

View full text Add to dashboard Cite

Mitochondria, endoplasmic reticulum (ER), cytoplasmic lipid droplets (CLD), and Golgi vesicles use cross talk to control hepatocyte metabolism, growth, and stress. Interpretation of ultrastructural change requires knowledge of how cross talk pathways function, how differential activation of hepatocellular signals influences organelle structure, and how organelles position themselves to become central hubs for stress responses. Mitochondria, by coupling energy production to pathways for protection, form critical platforms for innate signaling. Mitochondrial outer and inner membranes activate channels and signals to translocate peptides that drive oxidative phosphorylation, b-oxidation of fatty acids, and calcium ion (Ca 2þ ) flux. In cell stress, mitochondrial signals initiate fusion and fission, reactive oxygen species (ROS) control, autophagy, apoptosis, and senescence. Specialized tethering proteins tie mitochondria to ER to support translocation of metabolites. For Ca 2þ translocation, ER pores are connected to mitochondrial voltage-dependent anion channels, and for mitochondrial fission, unique membrane proteins pull ER to mitochondria. In toxic injury, cytosolic cytokines translocate to alter metabolism. Toxic effects on ER lipid synthesis lead to Golgi vesicle reduplication and transport of perilipin and other protein cargos into CLDs. How cellular proteostasis, oxidative homeostasis, and ion balance are maintained depend upon the effectiveness of mitochondrial ROS defense responses, unfolded protein responses in mitochondria and ER, and other organelle defenses.

show abstract

Action of Pasteurella multocida toxin on Gαq is persistent and independent of interaction with G-protein-coupled receptors

Cited by 20 publications

References 34 publications

Activation of Gαi and Subsequent Uncoupling of Receptor-Gαi Signaling by Pasteurella multocida Toxin

Activation of Gαi and Subsequent Uncoupling of Receptor-Gαi Signaling by Pasteurella multocida Toxin

Pasteurella multocida toxin activation of heterotrimeric G proteins by deamidation

Ultrastructural Pathology and Interorganelle Cross Talk in Hepatotoxicity

Contact Info

Product

Resources

About