Actin activates Pseudomonas aeruginosa ExoY nucleotidyl cyclase toxin and ExoY-like effector domains from MARTX toxins

Alexander Belyy (1, 2) , Dorothée Raoux-Barbot (1) , Cosmin Saveanu (3) , Abdelkader Namane (3) , Vasily Ogryzko (4) , Lina Worpenberg (1) , Violaine David (5) , Veronique Henriot (5) , Souad Fellous (5) , Christien Merrifield (5) , Elodie Assayag (1) , Daniel Ladant (1) , Louis Renault (5) , Undine Mechold (1)

1 Biochimie des Interactions Macromoléculaires / Biochemistry of Macromolecular Interactions
2 Gamaleya Research Center
3 Génétique des Interactions Macromoléculaires
4 UMR8126 - Signalisation, noyaux et innovations en cancérologie
5 I2BC - Institut de Biologie Intégrative de la Cellule

The nucleotidyl cyclase toxin ExoY is one of the virulence factors injected by the Pseudomonas aeruginosa type III secretion system into host cells. Inside cells, it is activated by an unknown eukaryotic cofactor to synthesize various cyclic nucleotide monophosphates. ExoY-like adenylate cyclases are also found in Multifunctional-Autoprocessing Repeats-in-ToXin (MARTX) toxins produced by various Gram-negative pathogens. Here we demonstrate that filamentous actin (F-actin) is the hitherto unknown cofactor of ExoY. Association with F-actin stimulates ExoY activity more than 10,000 fold in vitro and results in stabilization of actin filaments. ExoY is recruited to actin filaments in transfected cells and alters F-actin turnover. Actin also activates an ExoY-like adenylate cyclase MARTX effector domain from Vibrio nigripulchritudo. Finally, using a yeast genetic screen, we identify actin mutants that no longer activate ExoY. Our results thus reveal a new subgroup within the class II adenylyl cyclase family, namely actin-activated nucleotidyl cyclase (AA-NC) toxins.

Keywords: Guanylate cyclase; Saccharomyces cerevisiae; Mass spectrometry; Actin; ExoY; Pseudomonas aeruginosa; Adenylate cyclase

Domains: Life Sciences [q-bio]; Biochemistry, Molecular Biology; Life Sciences [q-bio]; Cellular Biology; Life Sciences [q-bio]; Microbiology and Parasitology; Bacteriology

Alexander Belyy, Dorothée Raoux-Barbot, Cosmin Saveanu, Abdelkader Namane, Vasily Ogryzko, et al.. Actin activates Pseudomonas aeruginosa ExoY nucleotidyl cyclase toxin and ExoY-like effector domains from MARTX toxins. Nature Communications, 2016, 7, pp.13582. ⟨10.1038/ncomms13582⟩. ⟨pasteur-01424743⟩