Proteins in sponges

Shimizu, K., Cha, J., Stucky, G.D. and Morse, D.E. (1998) Silicatein alpha Cathepsin L-like protein in sponge biosilica. Proceedings of the National Academy of Sciences of the United States of America, 95, 6234-6238. 

The amount of collagen varies from one species to another and from tissue to tissue within the same species. Collagen comprises as much as one third of the total protein in the vertebrate body and in certain invertebrates, such as sponges and echinoderms as well as corals186, collagen may account for an even larger proportion of the total protein of the organism. 

The activities of the purple fluid of the sea hare Aplysia dactylomela, such as toxic, antimicrobial and hemagglutinating properties, have been attributed to a substance of protein nature [332], Proteoglycans and adhesive glycoproteins present in the extracellular matrix of vertebrates, have also been reported in sponges. These molecules are probably involved in the cell adhesion systems of sponges [333], Recently, novel marine proteins have been reported, such as silicatein from sponge biosilica [334], and a metallothionein protein from the marine alga Fuats vesiculosus [335], Metallothioneins have also been isolated from Arctic... 

Okadaic acid is a polyether derivative of a 38-carbon fatty acid elaborated by marine dinoflagellates and accumulated in sponges and in mussels Halichondria okadal). It acts as a selective inhibitor of protein phosphatase-1 and -2A, and is used as a pharmacological and biochemical tool. 

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