Species-specific aggregation factor in sponges. I. Characterization of the large circular proteid particle

Ζahn, Rudolf K.; Müller, Werner; Geisert, M.; Reinmüller, Johannes; Michaelis, M.; Pondeljak, Vesna; Beyer, Rudolf

doi:10.1016/0045-6039(76)90006-3

Cited by 19 publications

(2 citation statements)

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“…The ratio between the acidic and basic amino acids is 2 : 1. Hence, the amino acid composition of lectin I is very similar to that of the Geodia aggregation factor [33]. Lectin I is a glycoprotein with a carbohydrate content of 9.9 ?<).…”

Section: Discussionmentioning

confidence: 98%

Characterization of the Trimeric, Self‐Recognizing Geodia cydonium Lectin I

Müller

Conrad

Schröder

et al. 1983

European Journal of Biochemistry

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A D-galactose-specific lectin I was extracted from the sponge Geodia cydonium and purified by affinity chromatography. The molecular weight of Iectin I as determined by high-pressure liquid gel chromatography, was found to be 36500 1300. Disc gel electrophoresis in the presence and in the absence of sodium dodecyl sulfate showed that lectin I is a trimer composed of three different subunits ( M , : 13 800,13 000 and 12200); two of the three subunits are linked by one disulfide bond. Isoelectric focusing gave a PI of 5.6 for the native molecule and a PI of 4.4 and of 7.4 for the subunits. The three subunits carry carbohydrate side chains, composed of D-galactose (94%) and of arabinose (5%). Based on experiments with lectins, the terminal i)-galactose residues are bound by p1+6 and/or fi1-4 glycosidic linkages. The Geodiu lectin I contains, besides two carbohydrate recognition sites, at least one receptor site for a second Iectin I molecule.Lectins are proteins (or glycoproteins) that bind carbohydrates and agglutinate cells; they have been isolated from viruses, bacteria and eukaryotes [l]. Since the initial work of Dodd et al. (21, a series of lectins have also been isolated from the oldest multicellular animals, the sponges [3 -61. In contrast to most other lectins, the biological role(s) of the sponge lectins are known to some extent. It has been demonstrated [7], that the D-galactose-specific lectin from Geodia cydoviium [5] is involved in the sorting-out of cells during reaggregation of allogeneic cells [S]. This lectin controls the activity of the cell membrane-associated antiaggregation receptor [9] by reversible binding to its D-galactose termini. This receptor, in its active state, has been shown to dissociate the complex, formed between the aggregation factor and the aggregation receptor [7, 81. In the xenogeneic system, using cells from the sponge Tethya lyncurium, the Geodia lectin causes cell agglutination [lo]. Later, evidence was presented suggesting that the lectin from Dictyostelium discoideum plays an analogous role in cellcell adhesion of cellular slime molds [II, 121. In previous reports on the properties of the Geodia lectin, two main aspects have been studied; firstly, the relationship between the hemagglutinin and the aggregation factor [5] and secondly, the mitogenic activity of the lectin for human lymphocytes [6]. In the present contribution a detailed physicochemical characterization of the Geodia lectin I (the main lectin in this sponge) is given, demonstrating that it is a trimer of a molecular weight of 36 500, with the property to react with D-galactose termini of its own protein species. These two characteristics have not yet been observed with other lectins. One lectin from rat liver membranes has been described [13], which binds to its own galactose residues after a pretreatment with neuraminidase. MATERIALS AND METHODS Lectin Extraction and PurificationThe siliceous sponge Geodia cydoniurn (Jam.) was collected near Rovinj (Mediterranean Sea) and the lectins were isolatedAhhrev...

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Section: Discussionmentioning

confidence: 98%

Characterization of the Trimeric, Self‐Recognizing Geodia cydonium Lectin I

Müller

Conrad

Schröder

et al. 1983

European Journal of Biochemistry

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“…Figure lb shows the normal aspect of cell-cell contact (in the absence of the AF complex). The thickness of the fibrillary core structure of the AF, which is not deformable under the conditions used, is 23 nm [22]. Hence, these AF structures should be visible even at a low magnification of 15,OOOX.…”

Section: Electron Microscopical Aspect Of Plasma Membranesmentioning

confidence: 98%

Sponge aggregation factor: In situ localization by fluorescent monoclonal antibody techniques

Gramzow¹,

Dorn

Steffen³

et al. 1986

J of Cellular Biochemistry

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The aggregation factor (AF) from sponges mediates a heterophilic interaction of homologous cells. Applying electron microscopical means, we succeeded only very rarely in identifying the 90 S AF particle in tissue sections from Geodia cydonium. By means of a fluorescent antibody technique, we have now localized the cell binding domain of the AF in situ. Previous studies in this laboratory have led to the identification of the 47-kDa cell binding protein of the AF, using the monoclonal antibody (mab) 5D2-D11 [Gramzow M, Bachmann M, Zahn RK, Uhlenbruck G, Dorn A, Müller WEG, J Cell Biol, 102: 1344-1349, 1986]. This mab and mab 7D5, directed against a 92-kDa protein in the AF complex, were chosen for the fluorescent studies. By using mab 5D2-D11, the plasma membranes of cells from different regions in the sponge could be brightly stained. However, mab 7D5 reacted only very weakly with the sponge surfaces. By applying the immuno-blotting technique it was furthermore demonstrated that the cell binding protein is present both in the associated form with AF complex and in a free state. Moreover, it was established that the 47-kDa binding protein is not present in homologous glycoconjugates, lectin, or collagen; these components are known to be involved in cell-matrix interaction.

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