Cyclic nucleotide-dependent protein kinases. IV. Widespread occurrence of adenosine 3',5'-monophosphate-dependent protein kinase in various tissues and phyla of the animal kingdom

Adenosine 3',5'-monophosphate-dependent protein kinase activity was found in about thirty sources including many mammalian tissues as well as species representative of eight different invertebrate phyla. The data support a unifying theory for the mechanism of action of adenosine 3',5'-monophosphate, namely that its many and diverse effects are mediated through activation of tissue-specific protein kinases.

Bifunctional Small Molecules Are Biomimetic Catalysts for Silica Synthesis at Neutral pH

Silicatein is an enzyme isolated from the biosilica produced by the marine demosponge, Tethya aurantia. Once isolated from the sponge, silicatein can be used in vitro to catalyze the hydrolysis and direct polycondensation of a wide variety of alkoxide, ionic, and organometallic precursors to the corresponding chalcogens at standard temperature and pressure and neutral pH. On the basis of these results, an array of small molecules that mimic the unique physiochemical environment found in the enzyme active site was investigated for catalytic activity in the formation of silica from silicon alkoxides at neutral pH. The most successful of these biomimetic catalysts (cysteamine) was used to encapsulate firefly luciferase, green and blue fluorescent proteins (GFP, BFP), and Escherichia coli cells expressing GFP in silica matrixes. The benign conditions required for the catalysis of synthesis of these silica composites does not impair the activities of the encapsulated enzyme, fluorescent proteins, or live cells as shown by fluorescence measurements. In conjunction with microcontact printing, this biomimetically catalyzed encapsulation method has been used to produce patterned functional arrays of silica nanoparticulate composite materials.

Specific phosphorylation of proteins in pore complex-laminae from the sponge Geodia cydonium by the homologous aggregation factor and phorbol ester. Role of protein kinase C in the phosphorylation of DNA topoisomerase II

We have recently shown that the aggregation factor (AF) from the sponge Geodia cydonium stimulates DNA synthesis in quiescent, dissociated cells from the same organism; this event was correlated with the release of the two second messengers: inositol trisphosphate and diacylglycerol. Here we describe that after binding of the AF to the plasma membrane-bound aggregation receptor, a rapid and drastic increase in the incorporation of 32Pi into a series of proteins in the pore complex-lamina fraction occurs. Addition of the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate, to quiescent cells resulted in a similar stimulation of phosphorylation of nuclear proteins. Among them we have selected one protein with a polypeptide Mr of 170,000 (pp170) for detailed studies. By immunoblotting pp170 was identified as DNA topoisomerase II. In vitro studies with nuclei and purified, homogeneous protein kinase C together with the required activators of this enzyme also showed a phosphorylation of pp170. After phosphorylation, DNA topoisomerase II activity was found to be 2.5-fold that of the non-phosphorylated enzyme. From these data we conclude that protein kinase C is involved in AF induced transmembrane signalling, ultimately leading to an initiation of DNA synthesis.

The temperature-signaling cascade in sponges involves a heat-gated cation channel, abscisic acid, and cyclic ADP-ribose

Sponges (phylum Porifera) are the phylogenetically oldest metazoan animals, their evolution dating back to 600 million years ago. Here we demonstrate that sponges express ADP-ribosyl cyclase activity, which converts NAD(+) into cyclic ADP-ribose, a potent and universal intracellular Ca(2+) mobilizer. In Axinella polypoides (Demospongiae, Axinellidae), ADP-ribosyl cyclase was activated by temperature increases by means of an abscisic acid-induced, protein kinase A-dependent mechanism. The thermosensor triggering this signaling cascade was a heat-activated cation channel. Elucidation of the complete thermosensing pathway in sponges highlights a number of features conserved in higher organisms: (i) the cation channel thermoreceptor, sensitive to heat, mechanical stress, phosphorylation, and anesthetics, shares all of the functional characteristics of the mammalian heat-activated background K(+) channel responsible for central and peripheral thermosensing; (ii) involvement of the phytohormone abscisic acid and cyclic ADP-ribose as its second messenger is reminiscent of the drought stress signaling pathway in plants. These results suggest an ancient evolutionary origin of this stress-signaling cascade in a common precursor of modern Metazoa and Metaphyta.

Early evolution of metazoan serine/threonine and tyrosine kinases: identification of selected kinases in marine sponges

The phylum Porifera (sponges) was the first to diverge from the common ancestor of the Metazoa. In this study, six cDNAs coding for protein-serine/threonine kinases (PS/TKs) are presented; they have been isolated from libraries obtained from the demosponges Geodia cydonium and Suberites domuncula and from the calcareous sponge Sycon raphanus. Sequence alignments of the catalytic domains revealed that two major families of PS/TK, the "conventional" (Ca(2+)-dependent) protein kinase C (PKC), the cPKC subfamily, as well as the "novel" (Ca(2+)-independent) PKC (nPKC), form two separate clusters. In each cluster, the sequence from S. raphanus diverges first. To approach the question about the origin of protein-tyrosine kinases (PTK), which are found only in Metazoa, we analyzed two additional PS/TKs which have been cloned from S. domuncula: the stress-responsive protein kinase (KRSvSD) and the protein-kinase-C-related kinase (PRKvSD). The construction of the phylogenetic tree, comprising the eight PS/TKs and the PTK cloned previously from G. cydonium, revealed that the PTK derived from the branch including the KRSvSD kinase. These data facilitate the first molecular approach to elucidate the origin of metazoan PTK within the PS/TK superfamily.

Phylogenetic position of the Hexactinellida within the phylum Porifera based on the amino acid sequence of the protein kinase C from Rhabdocalyptus dawsoni

Recent analyses of genes encoding proteins typical for multicellularity, especially adhesion molecules and receptors, favor the conclusion that all metazoan phyla, including the phylum Porifera (sponges), are of monophyletic origin. However, none of these data includes cDNA encoding a protein from the sponge class Hexactinellida. We have now isolated and characterized the cDNA encoding a protein kinase C, belonging to the C subfamily (cPKC), from the hexactinellid sponge Rhabdocalyptus dawsoni. The two conserved regions, the regulatory part with the pseudosubstrate site, the two zinc fingers, and the C2 domain, as well as the catalytic domain were used for phylogenetic analyses. Sequence alignment and construction of a phylogenetic tree from the catalytic domains revealed that the yeast Saccharomyces cerevisiae and the protozoan Trypanosoma brucei are at the base of the tree, while the hexactinellid R. dawsoni branches off first among the metazoan sequences; the other two classes of the Porifera, the Calcarea (the sequence from Sycon raphanus was used) and the Demospongiae (sequences from Geodia cydonium and Suberites domuncula were used), branch off later. The statistically robust tree also shows that the two cPKC sequences from the higher invertebrates Drosophila melanogaster and Lytechinus pictus are most closely related to the calcareous sponge. This finding was also confirmed by comparing the regulatory part of the kinase gene. We suggest, that (i) within the phylum Porifera, the class Hexactinellida diverged first from a common ancestor to the Calcarea and the Demospongiae, which both appeared later, and (ii) the higher invertebrates are more closely related to the calcareous sponges.

Sponge Paleogenomics Reveals an Ancient Role for Carbonic Anhydrase in Skeletogenesis

Sponges (phylum Porifera) were prolific reef-building organisms during the Paleozoic and Mesozoic approximately 542 to 65 million years ago. These ancient animals inherited components of the first multicellular skeletogenic toolkit from the last common ancestor of the Metazoa. Using a paleogenomics approach, including gene- and protein-expression techniques and phylogenetic reconstruction, we show that a molecular component of this toolkit was the precursor to the alpha-carbonic anhydrases (alpha-CAs), a gene family used by extant animals in a variety of fundamental physiological processes. We used the coralline demosponge Astrosclera willeyana, a "living fossil" that has survived from the Mesozoic, to provide insight into the evolution of the ability to biocalcify, and show that the alpha-CA family expanded from a single ancestral gene through several independent gene-duplication events in sponges and eumetazoans.

Molecular cloning of a tyrosine kinase gene from the marine sponge Geodia cydonium: a new member belonging to the receptor tyrosine kinase class II family

We have isolated and characterized a cDNA from the marine sponge Geodia cydonium coding for a new member of the tyrosine protein kinase (TK) family. The cDNA encodes a protein of M(r) = 68,710, termed GCTK, which is homologous to class II receptor tyrosine kinases (RTKs). GCTK contains conserved amino acids (aa) characteristic of all protein kinases, and the sequences DLATRN and PIRWMATE which are highly specific for TKs. Furthermore, the sequence N-L-Y-x(3)-Y-Y-R is highly homologous to the sequence D-[LIV]-Y-x(3)-Y-Y-R found only in class II RTKs. The sponge TK, when compared with mammalian class II RTKs, shows maximum 31% homology in the TK domain indicating that this the oldest member of class II RTK started to diverge from the common ancestral protein kinase approximately 650 million years ago. Using GCTK as a probe we identified three mRNA signals ranging from 2.6 to 0.6 kb. Kinase activity was localized only in the cell membranes from G. cydonium (M(r) = 65,000), and was not detected in the cytosol of this organism. Antibodies raised against a synthetic peptide, corresponding to the aa residues within the catalytic domain of the sponge TK, recognized strongly two proteins of M(r) = 65,000; these proteins, present in membrane fractions, also bound to the antiphosphotyrosine antibody. These data suggest that the TK cloned from the sponge is a membrane-associated 65 kDa protein. Moreover these results demonstrate that RTKs are present from the lowest group of multicellular eukaryotes, sponges, to mammals, and may suggest that RTKs are involved in a signal transduction pathway.

Sponges (Porifera) model systems to study the shift from immortal to senescent somatic cells: the telomerase activity in somatic cells

Sponges (Porifera) represent the lowest metazoan phylum, characterized by a pronounced plasticity in the determination of cell lineages. In a first approach to elucidate the molecular mechanisms controlling the switch from the cell lineage with a putative indefinite growth capacity to senescent, somatic cells, the activity of the telomerase as an indicator for immortality has been determined. The studies were performed with the marine demosponges Suberites domuncula and Geodia cydonium. It was found that the activity for the telomerase in the tissue of both sponges is high; a quantitative analysis revealed that the extract from S. domuncula contained 10.3 TPG units per 5000 cell equivalents and the one from G. cydonium 8.3 TPG units; hence the activity reached approximately 30-20% of the activity seen in telomerase-positive reference cells. In contrast, dissociated spherulous cells from G. cydonium, after an incubation period of 24 h, contained no detectable telomerase activity. From earlier studies it is known that isolated sponge cells do not proliferate. Based on these findings it is assumed that the separation of the senescent sponge cell lineage from the immortal germ/somatic cell lineage is triggered by the loss of contact with cell adhesion factors. First evidence is included which suggests that the final progress of the senescent, telomerase-negative cells to cell death is caused by apoptosis.

Silicateins--a novel paradigm in bioinorganic chemistry: enzymatic synthesis of inorganic polymeric silica

The inorganic matrix of the siliceous skeletal elements of sponges, that is, spicules, is formed of amorphous biosilica. Until a decade ago, it remained unclear how the hard biosilica monoliths of the spicules are formed in sponges that live in a silica-poor (<50 μM) aquatic environment. The following two discoveries caused a paradigm shift and allowed an elucidation of the processes underlying spicule formation; first the discovery that in the spicules only one major protein, silicatein, exists and second, that this protein displays a bio-catalytical, enzymatic function. These findings caused a paradigm shift, since silicatein is the first enzyme that catalyzes the formation of an inorganic polymer from an inorganic monomeric substrate. In the present review the successive steps, following the synthesis of the silicatein product, biosilica, and resulting in the formation of the hard monolithic spicules is given. The new insight is assumed to open new horizons in the field of biotechnology and also in biomedicine.

Silicateins, the major biosilica forming enzymes present in demosponges: protein analysis and phylogenetic relationship

Silicateins are enzymes, which are restricted to sponges (phylum Porifera), that mediate the catalytic formation of biosilica from monomeric silicon compounds. The silicatein protein is compartmented in the sponges in the axial filaments which reside in the axial canals of the siliceous spicules. In the present study silicatein has been isolated from the freshwater sponge Lubomirskia baicalensis where it occurs in isoforms with sizes of 23 kDa, 24 kDa and 26 kDa. Since the larger protein is glycosylated we posit that it is a processed form of one of the smaller size forms. The silicatein isoforms are post-translationally modified by phosphorylation; at least four isoforms exist with pI's of 5.4, of 5.2, of 4.9 and of 4.7. Surprisingly silicatein not only mediates polymerization of silicate, but also displays proteolytic activity which is specific for cathepsin L enzymes, thus underscoring the high relationship of the silicateins to cathepsin L. The cDNAs from L. baicalensis for silicatein and cathepsin L, as well as the respective genes, were cloned. It was found that the five introns present in the sponge genes are highly conserved up to human cathepsin L. This analysis has been completed by sequencing of two silicatein genes (both for silicatein-alpha and -beta) and of cathepsin L from another demosponge, Suberites domuncula. A comprehensive phylogenetic analysis with these new sequences shed new light upon the evolution of cathepsin L and silicatein families which occurred at the base of the metazoan phyla. It is concluded, that in parallel with the emergence of these enzymes at first the number of introns increased, especially in the coding region of the mature enzyme. Later in evolution the number of introns decreased again. We postulate that modification of the catalytic triad, especially of its first amino acid, is a suitable target for a chemical modulation of enzyme function of the silicateins/cathepsin L.

Induction of (2'-5')oligoadenylate synthetase in the marine sponges Suberites domuncula and Geodia cydonium by the bacterial endotoxin lipopolysaccharide

Recent studies have shown that the Porifera, with the examples of the demosponges Suberites domuncula and Geodia cydonium, comprise a series of pathways found also in the immune system of Deuterostomia, such as vertebrates, but are absent in Protostomia, with insects or nematodes as examples. One pathway is the (2'-5')oligoadenylate synthetase [(2-5)A synthetase] system. In the present study we show that crude extracts from tissue of S. domuncula collected from the sea display a considerable amount of (2-5)A synthetase activity; 16% of the ATP substrate is converted to the (2-5)A product, while tissue from specimens which were kept for 6 months in an aquarium shows only 1% of conversion. As aquarium animals show a lower bacterial load, those specimens were treated for the experiments with the bacterial endotoxin lipopolysaccharide (LPS); they responded to LPS with a stimulation of the (2-5)A synthetase activity. To monitor if this effect can be obtained also on the in vitro level, primmorphs which comprise proliferating and differentiating cells, were incubated with LPS. Extracts obtained from LPS-treated primmorphs also convert ATP to the (2-5)A products mediated by the synthetase. In parallel to this effect on protein level, LPS causes after an incubation period of 12 h also an increase in the steady-state level of the transcripts encoding the putative (2-5)A synthetase. It is postulated that in sponges the (2-5)A synthetase is involved in antimicrobial defense of the animals.

Molecular phylogeny of the Astrophorida (Porifera, Demospongiae(p)) reveals an unexpected high level of spicule homoplasy

BACKGROUND

The Astrophorida (Porifera, Demospongiae(p)) is geographically and bathymetrically widely distributed. Systema Porifera currently includes five families in this order: Ancorinidae, Calthropellidae, Geodiidae, Pachastrellidae and Thrombidae. To date, molecular phylogenetic studies including Astrophorida species are scarce and offer limited sampling. Phylogenetic relationships within this order are therefore for the most part unknown and hypotheses based on morphology largely untested. Astrophorida taxa have very diverse spicule sets that make them a model of choice to investigate spicule evolution.

METHODOLOGY/PRINCIPAL FINDINGS

With a sampling of 153 specimens (9 families, 29 genera, 89 species) covering the deep- and shallow-waters worldwide, this work presents the first comprehensive molecular phylogeny of the Astrophorida, using a cytochrome c oxidase subunit I (COI) gene partial sequence and the 5' end terminal part of the 28S rDNA gene (C1-D2 domains). The resulting tree suggested that i) the Astrophorida included some lithistid families and some Alectonidae species, ii) the sub-orders Euastrophorida and Streptosclerophorida were both polyphyletic, iii) the Geodiidae, the Ancorinidae and the Pachastrellidae were not monophyletic, iv) the Calthropellidae was part of the Geodiidae clade (Calthropella at least), and finally that v) many genera were polyphyletic (Ecionemia, Erylus, Poecillastra, Penares, Rhabdastrella, Stelletta and Vulcanella).

CONCLUSION

The Astrophorida is a larger order than previously considered, comprising ca. 820 species. Based on these results, we propose new classifications for the Astrophorida using both the classical rank-based nomenclature (i.e., Linnaean classification) and the phylogenetic nomenclature following the PhyloCode, independent of taxonomic rank. A key to the Astrophorida families, sub-families and genera incertae sedis is also included. Incongruences between our molecular tree and the current classification can be explained by the banality of convergent evolution and secondary loss in spicule evolution. These processes have taken place many times, in all the major clades, for megascleres and microscleres.

Phospholipase C cDNAs from sponge and hydra: antiquity of genes involved in the inositol phospholipid signaling pathway

To know whether or not the set of genes involved in the inositol phospholipid signaling pathway already existed in the early evolution of animals, we carried out cloning of cDNAs encoding phospholipase Cs (PLCs) from Ephydatia fluviatilis (freshwater sponge) and Hydra magnipapillata strain 105 (hydra). We isolated two PLC cDNAs, PLC-betaS and PLC-gammaS, from sponge and three cDNAs, PLC-betaH1, PLC-betaH2, and PLC-deltaH, from hydra. From the domain organization and the divergence pattern in the PLC family tree, the sponge PLC-betaS and PLC-gammaS and the hydra PLC-deltaH are possibly homologous to the vertebrate PLC-beta, PLC-gamma and PLC-delta subtypes, respectively. A detailed phylogenetic analysis suggests that the hydra PLC-betaH1 and PLC-betaH2 are homologs of the vertebrate PLC-beta1/2/3/Drosophila PLC21 and the vertebrate PLC-beta4/Drosophila norpA, respectively. A phylogenetic analysis of the PLC family and the protein kinase C (PKC) family, together with that of the G protein alpha subunit (Galpha) family, revealed that the origin of the set of genes G(alpha)q, PLC, PKC involved in the inositol phospholipid signaling pathway is very old, going back to dates before the parazoan-eumetazoan split, the earliest branching among extant animal phyla.

Origin of the interferon-inducible (2'-5')oligoadenylate synthetases: cloning of the (2'-5')oligoadenylate synthetase from the marine sponge Geodia cydonium

In vertebrates cytokines mediate innate (natural) immunity and protect them against viral infections. The cytokine interferon causes the induction of the (2'-5')oligoadenylate synthetase [(2-5)A synthetase], whose product, (2'-5')oligoadenylate, activates the endoribonuclease L which in turn degrades (viral) RNA. Three isoforms of (2-5)A synthetases exist, form I (40-46 kDa), form II (69 kDa), and form III (100 kDa). Until now (2-5)A synthetases have only been cloned from birds and mammals. Here we describe the cloning of the first putative invertebrate (2-5)A synthetase from the marine sponge Geodia cydonium. The deduced amino acid sequence shows signatures characteristic for (2-5)A synthetases of form I. Phylogenetic analysis of the putative sponge (2-5)A synthetase indicates that it diverged first from a common ancestor of the hitherto known members of (vertebrate) (2-5)A synthetases I, (2-5)A synthetases II and III. Moreover, it is suggested that the (2-5)A synthetases II and III evolved from this common ancestor (very likely) by gene duplication. Together with earlier results on the existence of the (2'-5')oligoadenylates in G. cydonium, the data presented here demonstrate that also invertebrates, here sponges, are provided with the (2-5)A system. At present, it is assumed that this system might be involved in growth control, including control of apoptosis, and acquired its additional function in innate immune response in evolutionarily younger animals, in vertebrates.

Enzymatic production of biosilica glass using enzymes from sponges: basic aspects and application in nanobiotechnology (material sciences and medicine)

Biomineralization, biosilicification in particular (i.e. the formation of biogenic silica, SiO2), has become an exciting source of inspiration for the development of novel bionic approaches following "nature as model". Siliceous sponges are unique among silica forming organisms in their ability to catalyze silica formation using a specific enzyme termed silicatein. In this study, we review the present state of knowledge on silicatein-mediated "biosilica" formation in marine sponges, the involvement of further molecules in silica metabolism and their potential application in nanobiotechnology and medicine.

Phylogenetic relationships of the marine Haplosclerida (Phylum Porifera) employing ribosomal (28S rRNA) and mitochondrial (cox1, nad1) gene sequence data

The systematics of the poriferan Order Haplosclerida (Class Demospongiae) has been under scrutiny for a number of years without resolution. Molecular data suggests that the order needs revision at all taxonomic levels. Here, we provide a comprehensive view of the phylogenetic relationships of the marine Haplosclerida using many species from across the order, and three gene regions. Gene trees generated using 28S rRNA, nad1 and cox1 gene data, under maximum likelihood and Bayesian approaches, are highly congruent and suggest the presence of four clades. Clade A is comprised primarily of species of Haliclona and Callyspongia, and clade B is comprised of H. simulans and H. vansoesti (Family Chalinidae), Amphimedon queenslandica (Family Niphatidae) and Tabulocalyx (Family Phloeodictyidae), Clade C is comprised primarily of members of the Families Petrosiidae and Niphatidae, while Clade D is comprised of Aka species. The polyphletic nature of the suborders, families and genera described in other studies is also found here.

Sponge homologs of vertebrate protein tyrosine kinases and frequent domain shufflings in the early evolution of animals before the parazoan-eumetazoan split

The protein tyrosine kinases (PTKs) diverged specifically in animal lineages by gene duplications and domain shufflings to form a large protein family comprising diverse subfamilies with distinct domain organizations and functions. On the basis of a phylogenetic tree inferred from a comparison of the shared kinase domains, we previously showed that gene duplications that gave rise to diverse subfamilies predate the divergence of parazoans and eumetazoans. There is, however, still a possibility that, although the kinase domain duplications are ancient events, the domain shufflings that gave rise to different subfamilies with distinct domain organization are more recent event than the kinase domain duplications. To clarify this problem, we have determined the complete sequences of 15 sponge PTKs and have compared the domain organizations of these sponge PTKs and those of eumetazoans. For each of ten sponge PTKs out of 15 analyzed here, a possible eumetazoan (human and Drosophila) ortholog has been identified. The sponge and eumetazoan orthologs are virtually identical in domain organization and belong to the same subfamily in the PTK family tree for each of ten orthologous pairs, except for one subfamily in which a considerable deletions and/or insertions of domains are observed. This result suggests that most, if not all, of the domain shufflings, together with gene duplications, are very old, going back to dates before the parazoan-eumetazoan split, the earliest divergence among extant animal phyla.

Role of phospholipase A2 in the stimulation of sponge cell proliferation by homologous lectin

Using the Geodia cydonium system, we showed that after incubation of competent sponge cells in the presence of lectin, phospholipase A2 was released from the cells. The substrates for this enzyme, phosphatidylethanolamine and phosphatidylcholine, were identified in the extracellular material of sponge tissue. In addition, the phospholipase A2 inhibitor calelectrin was identified by immunobiochemical techniques; this molecule was associated with the aggregation factor. Reconstitution experiments strongly suggested that phospholipase A2 catalyzed the release of arachidonic acid, which is then taken up by the cells. Intracellularly, arachidonic acid was metabolized primarily to prostaglandin E2. Inhibition studies revealed that prostaglandin E2 is involved in the ultimate increase of DNA synthesis. These findings suggest that the phospholipase A2-arachidonic acid system is involved in the matrix-initiated signal transduction pathway in sponges.

Heat stress-activated, calcium-dependent nitric oxide synthase in sponges

The presence of Ca(2+)-dependent, heat-stress-activated nitric oxide synthase (NOS) activity in peculiarly shaped, fusiform, and dendritic sponge cells is described for the first time. The NOS activity was evidenced evaluating the conversion of radioactive citrulline from [(14)C]arginine in intact cells from two different species that are phylogenetically unrelated in the class of Demospongiae: Axinella polypoides and Petrosia ficiformis. The production of nitrogen monoxide (NO) was confirmed by electron paramagnetic resonance analysis, and the histochemistry technique of NADPH diaphorase showed a specific localization of NOS activity in a particular network of dendritic cells in the sponge parenchyma. Sponges are the most primitive metazoan group; their evolution dates back 600 million years. The presence of environmental stress-activated NOS activity in these organisms may prove to be the most ancient NO-dependent signaling network in the animal kingdom.