Circular proteoglycans from sponges: first members of the spongican family.
Species-specific cell adhesion in marine sponges is mediated by a new family of modular proteoglycans whose general supramolecular structure resembles that of hyalectans. However, neither their protein nor their glycan moieties have significant sequence homology to other proteoglycans, despite having protein subunits equivalent to link proteins and to proteoglycan monomer core proteins, and glycan subunits equivalent to hyaluronan and to the glycosaminoglycans of hyalectans. In some species, these molecular components are assembled into a structure with a circular core formed by the link protein- and hyaluronan-like subunits. Besides their involvement in cell adhesion, these sponge proteoglycans, for which we propose the term spongicans, participate in signal transduction processes and are suspected to play a role in sponge self-nonself recognition. Their in vivo roles and the mild methods used to purify large amounts of functionally active spongicans make them ideal models to study the functions and possible new applications of proteoglycans in biomedical research.
Fernàndez-Busquets
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Research Center for Bioelectronics and Nanobioscience, Barcelona Science Park, University of Barcelona, Josep Samitier 1-5, E-08028 Barcelona, Spain. busquets@qf.ub.es
Burger
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins; D006820:Hyaluronic Acid / Q000737:chemistry; D008562:Membrane Glycoproteins / Q000648:ultrastructure; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000378:metabolism; D011161:Porifera / Q000737:chemistry*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D011509:Proteoglycans / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D015398:Signal Transduction; D013045:Species Specificity; D020080:Tandem Repeat Sequences; D000099249:Proteoglycan Link Protein
D002118:Calcium; D015815:Cell Adhesion Molecules; D016326:Extracellular Matrix Proteins; D006820:Hyaluronic Acid; D008562:Membrane Glycoproteins; D010456:Peptides, Cyclic; D011506:Proteins; D011509:Proteoglycans; D000099249:Proteoglycan Link Protein; C013065:cell aggregation factors