Toxic polypeptides of the hydra—a bioinformatic approach to cnidarian allomones

Sher, Daniel; Knebel, Alin; Bsor, Tamar; Nesher, Nir; Tal, Tzachy; Morgenstern, David; Cohen, Eran; Fishman, Yelena; Zlotkin, Eliahu

doi:10.1016/j.toxicon.2005.02.004

Cited by 44 publications

(37 citation statements)

References 72 publications

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“…As such, they have developed a highly complex and versatile array of protein and polypeptide toxins (neurotoxins, cytolysins, and phospholipases) aimed to paralyze the prey and prepare it for digestion (1). These toxins are generally thought to be stored and delivered into the prey through the highly developed stinging cells, nematocysts (2).…”

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confidence: 99%

Hydralysins, a New Category of β-Pore-forming Toxins in Cnidaria

Sher¹,

Fishman²,

Zhang³

et al. 2005

Journal of Biological Chemistry

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Cnidaria are venomous animals that produce diverse protein and polypeptide toxins, stored and delivered into the prey through the stinging cells, the nematocytes. These include pore-forming cytolytic toxins such as well studied actinoporins. In this work, we have shown that the non-nematocystic paralytic toxins, hydralysins, from the green hydra Chlorohydra viridissima comprise a highly diverse group of ␤-pore-forming proteins, distinct from other cnidarian toxins but similar in activity and structure to bacterial and fungal toxins. Functional characterization of hydralysins reveals that as soluble monomers they are rich in ␤-structure, as revealed by far UV circular dichroism and computational analysis. Hydralysins bind erythrocyte membranes and form discrete pores with an internal diameter of ϳ1.2 nm. The cytolytic effect of hydralysin is cell type-selective, suggesting a specific receptor that is not a phospholipid or carbohydrate. Multiple sequence alignment reveals that hydralysins share a set of conserved sequence motifs with known pore-forming toxins such as aerolysin, ⑀-toxin, ␣-toxin, and LSL and that these sequence motifs are found in and around the poreforming domains of the toxins. The importance of these sequence motifs is revealed by the cloning, expression, and mutagenesis of three hydralysin isoforms that strongly differ in their hemolytic and paralytic activities. The correlation between the paralytic and cytolytic activities of hydralysin suggests that both are a consequence of receptor-mediated pore formation. Hydralysins and their homologues exemplify the wide distribution of ␤-pore formers in biology and provide a useful model for the study of their molecular mode of action.

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confidence: 99%

Hydralysins, a New Category of β-Pore-forming Toxins in Cnidaria

Sher¹,

Fishman²,

Zhang³

et al. 2005

Journal of Biological Chemistry

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“…It is here that Hydra as a have detected three different type III PLA2 proteins in extracts from Hydra magnipapillata nematocysts. These PLA2s are similar, on the one hand, to toxins found in bee, lizard and jellyfish venoms (Lotan et al, 1995, Lotan et al, 1996, Sher et al, 2005b, and on the other hand to mammalian PLA2s expressed in kidney, heart, liver and muscles (Valentin et al, 2000) (Fig 1A). In addition to the nematocyst PLA2s, the Hydra genome contains another three putative genes containing similar PLA2 domains, whose role is currently unclear (Fig 1A).…”

Section: Type III Secretory Phospholipase A2s (Pla2s)mentioning

confidence: 62%

“…A similar domain is found in many proteins potentially involved in pathogenesis, although its role is not clear. Additionally, more distant SCP/ CRISP domains are found in several toxins from wasps, lizards, snakes and cone snails (Hwang et al, 2007, Sher et al, 2005b. In addition to this putative toxin, we have detected another three proteins in the nematocyst extract containing one or more ShK-like domains.…”

Section: Toxins With Shk-like Domainsmentioning

confidence: 75%

“…Recent approaches making use of the ever-increasing amount of genetic data available have revealed the occurrence of transcripts with a high level of homology to at least eight groups of previously-described toxins (Sher et al, 2005b, Sher andZlotkin, 2009). Two of these, actinoporins and ShK-domain containing proteins, have been shown to be associated with nematocysts (Hwang et al, 2007).…”

Section: What Constitutes the Chemical Armament Of Hydra?mentioning

confidence: 99%

“…pre-and post-synaptic ion channels, neurotransmitter receptors) (Fry et al, 2009). From an ecological standpoint, Hydra belongs to this group of organisms, yet to date no genes or transcripts have been detected encoding short peptide neurotoxins (Sher et al, 2005b, Sher andZlotkin, 2009), and biochemical fractionation of the nematocyst venom supports the lack of low molecular weight (< 20 kDa) toxins (Klug et al, 1989a).…”

Section: A B Cmentioning

confidence: 99%

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What Hydra can teach us about chemical ecology how a simple, soft organism survives in a hostile aqueous environment

Rachamim

Sher

2012

Int. J. Dev. Biol.

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Hydra and its fellow cnidarians -sea anemones, corals and jellyfish -are simple, mostly sessile animals that depend on bioactive chemicals for survival. In this review, we briefly describe what is known about the chemical armament of Hydra, and detail future research directions where Hydra can help illuminate major questions in chemical ecology, pharmacology, developmental biology and evolution. Focusing on two groups of putative toxins from Hydra -phospholipase A2s and proteins containing ShK and zinc metalloprotease domains, we ask: how do different venom components act together during prey paralysis? How is a venom arsenal created and how does it evolve? How is the chemical arsenal delivered to its target? To what extent does a chemical and biotic coupling exist between an organism and its environment? We propose a model whereby in Hydra and other cnidarians, bioactive compounds are secreted both as localized point sources (nematocyte discharges) and across extensive body surfaces, likely combining to create complex "chemical landscapes". We speculate that these cnidarian-derived chemical landscapes may affect the surrounding community on scales from microns to, in the case of coral reefs, hundreds of kilometers.

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Marine Protein Toxins

Nagai¹

2012

Handbook of Marine Natural Products

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Toxic polypeptides of the hydra—a bioinformatic approach to cnidarian allomones

Cited by 44 publications

References 72 publications

Hydralysins, a New Category of β-Pore-forming Toxins in Cnidaria

Hydralysins, a New Category of β-Pore-forming Toxins in Cnidaria

What Hydra can teach us about chemical ecology how a simple, soft organism survives in a hostile aqueous environment

Marine Protein Toxins

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