Phospholipase A activity of adenylate cyclase toxin?

Mašín, Jiří; Osička, Radim; Bumba, Ladislav; Šebo, Peter

doi:10.1073/pnas.1722588115

Cited by 5 publications

(10 citation statements)

References 9 publications

(4 reference statements)

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“…A putative contamination of our toxin by OMPLA seems, therefore, unconvincing, and even if it happened it would be an "inactive contaminant." Regarding the supposition of loss of RTX domain function of ACT-D1079A by protein degradation, mentioned in the Masin et al (1) letter, our data (CD, binding to liposomes and to macrophages, and calcium response) do not support it. In relation to the methyl arachidonyl fluorophosphonate (MAFP)-treated ACT data in cells, we show that control ACT (no MAFP) treated identically (dialysis) retains its PLA activity in cells, and the inhibitory effect of MAFP on the ACT-PLA activity was also proved in the PLA assays in vitro, in which treatment of the samples did not include the dialysis step.…”

contrasting

confidence: 92%

“…OMPLA has lysophospholipase activity (3-6), and has two calcium binding sites with micromolar affinity (7). What Masin et al (1) argue involves that the "putative contaminant" is not randomly present in our preparations, but rather that it would have to be, precisely, "more" present in ACT, and "less" present in S606A, and absent (?) in D1079A preparations, to fit our data.…”

mentioning

confidence: 92%

“…Furthermore, the MAFP-induced inhibition is not the single proof to conclude that ACT has PLA activity and that this activity is involved in translocation; the data with the PLA-inactive ACT-S606A mutant lead to the same conclusions. Regarding previous data by Osicka et al (9) showing that insertion of a tripeptide at position 607 of ACT sequence, adjacent to Ser-606, has no effect on AC delivery, Masin et al (1) failed to mention that insertion of longer peptides (nona-and undecapeptides) does reduce AC translocation.…”

mentioning

confidence: 94%

“…In their letter, Masin et al (1) affirm that a "varying extent of contamination" of adenylate cyclase toxin (ACT) and ACT-S606A purified toxin preparations, by the phospholipase A (PLA) enzyme from the outer membrane (OMPLA) of the producing Escherichia coli cells, could easily account for our finding that ACT has intrinsic PLA activity (2). E. coli OMPLA is an integral membrane protein of very low abundance (∼200-500 copies per cell) (3), whose extraction from the bacterial membrane is particularly difficult, requiring harsh detergents (SDS) for its extraction-solubilization (3)(4)(5)(6).…”

mentioning

confidence: 95%

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Reply to Masin et al: To be or not to be a phospholipase A

Ostolaza¹

2018

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

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confidence: 92%

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confidence: 92%

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confidence: 94%

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confidence: 95%

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Reply to Masin et al: To be or not to be a phospholipase A

Ostolaza¹

2018

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

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“…USA . [ 37 ]). Although Gonzáles-Bullón et al claimed to have discovered a new enzymatic activity of CyaA, the enzyme kinetics of the putative PLA activity of CyaA were not shown.…”

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confidence: 99%

Bordetella Pertussis Adenylate Cyclase Toxin Does Not Possess a Phospholipase A Activity; Serine 606 and Aspartate 1079 Residues Are Not Involved in Target Cell Delivery of the Adenylyl Cyclase Enzyme Domain

Bumba

Mašín

Osičková

et al. 2018

Toxins

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The adenylate cyclase toxin-hemolysin (CyaA, ACT, or AC-Hly) plays a crucial role in virulence and airway colonization capacity of the whooping cough agent Bordetella pertussis. The toxin penetrates target cell membranes and exhibits three distinct biological activities. A population of CyaA conformers forms small cation-selective pores that permeabilize the cell membrane for potassium efflux, which can provoke colloid-osmotic (oncotic) cell lysis. The other two activities are due to CyaA conformers that transiently form calcium influx conduits in the target cell membrane and translocate the adenylate cyclase (AC) enzyme into cytosol of cells. A fourth putative biological activity has recently been reported; an intrinsic phospholipase A (PLA) activity was claimed to be associated with the CyaA polypeptide and be involved in the mechanism of translocation of the AC enzyme polypeptide across cell membrane lipid bilayer. However, the conclusions drawn by the authors contradicted their own results and we show them to be erroneous. We demonstrate that highly purified CyaA is devoid of any detectable phospholipase A1 activity and that contrary to the published claims, the two putative conserved phospholipase A catalytic residues, namely the Ser606 and Asp1079 residues, are not involved in the process of membrane translocation of the AC domain of CyaA across target membranes.

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Role of Major Toxin Virulence Factors in Pertussis Infection and Disease Pathogenesis

Scanlon

Skerry

Carbonetti

2019

Advances in Experimental Medicine and Biology

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Bordetella pertussis produces several toxins that affect host-pathogen interactions. Of these, the major toxins that contribute to pertussis infection and disease are pertussis toxin, adenylate cyclase toxin-hemolysin and tracheal cytotoxin. Pertussis toxin is a multi-subunit protein toxin that inhibits host G protein-coupled receptor signaling, causing a wide array of effects on the host. Adenylate cyclase toxin-hemolysin is a single polypeptide, containing an adenylate cyclase enzymatic domain coupled to a hemolysin domain, that primarily targets phagocytic cells to inhibit their antibacterial activities. Tracheal cytotoxin is a fragment of peptidoglycan released by B. pertussis that elicits damaging inflammatory responses in host cells. This chapter describes these three virulence factors of B. pertussis, summarizing background information and focusing on the role of each toxin in infection and disease pathogenesis, as well as their role in pertussis vaccination.

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Phospholipase A activity of adenylate cyclase toxin?

Cited by 5 publications

References 9 publications

Reply to Masin et al: To be or not to be a phospholipase A

Reply to Masin et al: To be or not to be a phospholipase A

Bordetella Pertussis Adenylate Cyclase Toxin Does Not Possess a Phospholipase A Activity; Serine 606 and Aspartate 1079 Residues Are Not Involved in Target Cell Delivery of the Adenylyl Cyclase Enzyme Domain

Role of Major Toxin Virulence Factors in Pertussis Infection and Disease Pathogenesis

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