title: Proteome of Hydra nematocyst.
abstract: Stinging cells or nematocytes of jellyfish and other cnidarians represent one of the most poisonous and sophisticated cellular inventions in animal evolution. This ancient cell type is unique in containing a giant secretory vesicle derived from the Golgi apparatus. The organelle structure within the vesicle comprises an elastically stretched capsule (nematocyst) to which a long tubule is attached. During exocytosis, the barbed part of the tubule is accelerated with >5 million g in <700 ns, enabling a harpoon-like discharge (Nüchter, T., Benoit, M., Engel, U., Ozbek, S., and Holstein, T. W. (2006) Curr. Biol. 16, R316-R318). Hitherto, the molecular components responsible for the organelle's biomechanical properties were largely unknown. Here, we describe the proteome of nematocysts from the freshwater polyp Hydra magnipapillata. Our analysis revealed an unexpectedly complex secretome of 410 proteins with venomous and lytic but also adhesive or fibrous properties. In particular, the insoluble fraction of the nematocyst represents a functional extracellular matrix structure of collagenous and elastic nature. This finding suggests an evolutionary scenario in which exocytic vesicles harboring a venomous secretome assembled a sophisticated predatory structure from extracellular matrix motif proteins.
authors.affiliation: Department of Molecular Evolution and Genomics, Centre for Organismal Studies, University of Heidelberg, D48149 Münster, Germany.
authors.forename: Prakash G
authors.initials: PG
authors.lastname: Balasubramanian
authors.affiliation: Department of Molecular Evolution and Genomics, Centre for Organismal Studies, University of Heidelberg, D48149 Münster, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Beckmann
authors.affiliation: Functional Proteome Analysis, German Cancer Research Center (DKFZ), 69120 Heidelberg, D48149 Münster, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Warnken
authors.affiliation: Functional Proteome Analysis, German Cancer Research Center (DKFZ), 69120 Heidelberg, D48149 Münster, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Schnölzer
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, D48149 Münster, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schüler
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, D48149 Münster, Germany.
authors.forename: Erich
authors.initials: E
authors.lastname: Bornberg-Bauer
authors.affiliation: Department of Molecular Evolution and Genomics, Centre for Organismal Studies, University of Heidelberg, D48149 Münster, Germany. Electronic address: holstein@uni-hd.de.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Holstein
authors.affiliation: Department of Molecular Evolution and Genomics, Centre for Organismal Studies, University of Heidelberg, D48149 Münster, Germany. Electronic address: suat.oezbek@cos.uni-heidelberg.de.
authors.forename: Suat
authors.initials: S
authors.lastname: Özbek
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D005089:Exocytosis / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006829:Hydra / Q000166:cytology / Q000378:metabolism*; D058894:Nematocyst / Q000166:cytology / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism*; D022142:Secretory Vesicles / Q000378:metabolism*
chemical_list: D016326:Extracellular Matrix Proteins; D020543:Proteome