Identification of a membrane-bound prepore species clarifies the lytic mechanism of actinoporins

Koldo Morante, Augusto Bellomio, David Gil-Cartón, Lorena Redondo-Morata, Jesús Sot, Simon Scheuring, Mikel Valle, Juan Manuel González-Mañas, Kouhei Tsumoto, Jose M.M. Caaveiro

Research output: Contribution to journalArticle

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Abstract

Pore-forming toxins (PFTs) are cytolytic proteins belonging to the molecular warfare apparatus of living organisms. The assembly of the functional transmembrane pore requires several intermediate steps ranging from a water-soluble monomeric species to the multimeric ensemble inserted in the cell membrane. The non-lytic oligomeric intermediate known as prepore plays an essential role in the mechanism of insertion of the class of β-PFTs. However, in the class of α-PFTs, like the actinoporins produced by sea anemones, evidence of membrane-bound prepores is still lacking. We have employed single-particle cryo-electron microscopy (cryo-EM) and atomic force microscopy to identify, for the first time, a prepore species of the actinoporin fragaceatoxin C bound to lipid vesicles. The size of the prepore coincides with that of the functional pore, except for the transmembrane region, which is absent in the prepore. Biochemical assays indicated that, in the prepore species, the N terminus is not inserted in the bilayer but is exposed to the aqueous solution. Our study reveals the structure of the prepore in actinoporins and highlights the role of structural intermediates for the formation of cytolytic pores by an α-PFT.

Original languageEnglish
Pages (from-to)19210-19219
Number of pages10
JournalJournal of Biological Chemistry
Volume291
Issue number37
DOIs
Publication statusPublished - Sep 9 2016

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Sea Anemones
Cryoelectron Microscopy
Atomic Force Microscopy
Military operations
Cell membranes
Electron microscopy
Assays
Atomic force microscopy
Cell Membrane
Membranes
Lipids
Water
Proteins
fragaceatoxin C
Warfare

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Identification of a membrane-bound prepore species clarifies the lytic mechanism of actinoporins. / Morante, Koldo; Bellomio, Augusto; Gil-Cartón, David; Redondo-Morata, Lorena; Sot, Jesús; Scheuring, Simon; Valle, Mikel; González-Mañas, Juan Manuel; Tsumoto, Kouhei; Caaveiro, Jose M.M.

In: Journal of Biological Chemistry, Vol. 291, No. 37, 09.09.2016, p. 19210-19219.

Research output: Contribution to journalArticle

Morante, K, Bellomio, A, Gil-Cartón, D, Redondo-Morata, L, Sot, J, Scheuring, S, Valle, M, González-Mañas, JM, Tsumoto, K & Caaveiro, JMM 2016, 'Identification of a membrane-bound prepore species clarifies the lytic mechanism of actinoporins', Journal of Biological Chemistry, vol. 291, no. 37, pp. 19210-19219. https://doi.org/10.1074/jbc.M116.734053
Morante K, Bellomio A, Gil-Cartón D, Redondo-Morata L, Sot J, Scheuring S et al. Identification of a membrane-bound prepore species clarifies the lytic mechanism of actinoporins. Journal of Biological Chemistry. 2016 Sep 9;291(37):19210-19219. https://doi.org/10.1074/jbc.M116.734053
Morante, Koldo ; Bellomio, Augusto ; Gil-Cartón, David ; Redondo-Morata, Lorena ; Sot, Jesús ; Scheuring, Simon ; Valle, Mikel ; González-Mañas, Juan Manuel ; Tsumoto, Kouhei ; Caaveiro, Jose M.M. / Identification of a membrane-bound prepore species clarifies the lytic mechanism of actinoporins. In: Journal of Biological Chemistry. 2016 ; Vol. 291, No. 37. pp. 19210-19219.
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