Characterization of a Novel Proteinous Toxin from Sea Anemone Actineria villosa

Abstract

The sea anemone Actineria villosa expresses a lethal protein toxin. We isolated a novel 120-kDa protein, Avt120, from partially purified toxin and found it to possess extremely strong lethal activity. The 3453-bp Avt120 gene translates to a 995-amino acid protein. The 50% lethal dose (LD 50 ) of purified Avt120 in mice was 85.17 ng.Among several tested cell lines, Colo205 cells were most sensitive to Avt120: 50% of them were damaged by 38.4 ng/ml Avt120. Avt120 exerted ATP degradation activity (10 µmol ATP·h -1 ·mg -1 ), which was strongly inhibited by ganglioside GM1 to decrease the cytotoxicity of Avt120.

Sea Anemone Membrane Attack Complex/Perforin Superfamily Demonstrates an Evolutionary Transitional State between Venomous and Developmental Functions

“…The clade containing only sea anemone sequences, however, includes proteins known to be a component of sea anemone venom profiles. Specifically, the sequences from P. semoni (PsTX60A and PsTX60B) and A. villosa (AvTX60B) have been isolated from nematocytes and shown to be toxic to shrimp and hemolytic toward sheep red blood cells ( Nagai et al 2002 ; Oshiro et al 2004 ; Satoh et al 2007 ; Uechi et al 2011 ). Using AlphaFold, analysis of the predicted structure of NveMACs 1 to 4 with the predicted structure of PsTX60A and PsTX60B showed broad overlap among all sequences, suggesting that potentially NveMACs 1 to 4 might also have hemolytic activity ( supplementary fig.…”

“…This family includes β-pore-forming toxins (PFTs) that are found in a wide variety of organisms from bacteria to mammals and are mostly employed for lysing cells by generating pores in their membranes ( Anderluh et al 2014 ). MACs were found to be toxins in the nematocysts of two sea anemones, Actineria villosa and Phyllodiscus semoni ( Nagai et al 2002 ; Oshiro et al 2004 ; Satoh et al 2007 ; Uechi et al 2011 ). Using comparative genomics and phylogenetics, as well as interrogating the publicly available cell atlases, we find that members of MAC were recruited into the nematocytes of the last common ancestor of Anthozoa (soft corals, stony corals, and sea anemones).…”

Sea anemone MACPF proteins demonstrate an evolutionary transitional state between venomous and developmental functions

“…The clade containing only sea anemone sequences, however, includes sequences known to be a part of the sea anemone venom profiles. Specifically, the sequences from P. semoni (PsTX60A and PsTX60B) and A. villosa (AvTX60B) that have been isolated from nematocytes and shown to be toxic to shrimp and hemolytic towards sheep red blood cells (26–29). Using Alphafold, analysis of the predicted structure of NveMAC 1-4 with the predicted structure ofPsTX60A and PsTX60B showed broad overlap among all sequences, suggesting that potentially NveMAC 1-4 might also have hemolytic activity ( Fig.…”

“…This family includes β-pore former toxins (PFTs) that are found in a wide variety of organisms from bacteria to mammals and are mostly employed for lysing cells by generating pores in their membranes (25). MACPFs were found to be toxins in the nematocysts of two sea anemones, Actineria villosa and Phyllodiscus semoni (26)(27)(28)(29). Using comparative genomics and phylogenetics, as well as interrogating the publicly available cell atlases, we find that members of MACPF were recruited into the nematocytes of the last common ancestor of Anthozoa (soft corals, stony corals and sea anemones).…”