0
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Lysosomal sialidase (neuraminidase-1) is targeted to the cell surface in a multiprotein complex that facilitates elastic fiber assembly.

      The Journal of Biological Chemistry
      Aorta, metabolism, Blotting, Western, Carbohydrates, chemistry, Cartilage, Catalysis, Cell Membrane, enzymology, Cells, Cultured, Chondrocytes, Chromatography, Affinity, Clostridium perfringens, DNA, Complementary, Electrophoresis, Polyacrylamide Gel, Fibroblasts, Galectins, Humans, Immunohistochemistry, Lysosomes, Microscopy, Electron, Microscopy, Fluorescence, Models, Biological, Muscle, Smooth, cytology, Neuraminidase, biosynthesis, Protein Binding, Protein Structure, Tertiary, Sialic Acids, Skin, Tropoelastin, beta-Galactosidase

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          We have established previously that the 67-kDa elastin-binding protein (EBP), identical to the spliced variant of beta-galactosidase, acts as a recyclable chaperone that facilitates secretion of tropoelastin. (Hinek, A., Keeley, F. W., and Callahan, J. W. (1995) Exp. Cell Res. 220, 312-324). We now demonstrate that EBP also forms a cell surface-targeted molecular complex with protective protein/cathepsin A and sialidase (neuraminidase-1), and provide evidence that this sialidase activity is a prerequisite for the subsequent release of tropoelastin. We found that treatment with sialidase inhibitors repressed assembly of elastic fibers in cultures of human skin fibroblasts, aortic smooth muscle cells, and ear cartilage chondrocytes and caused impaired elastogenesis in developing chick embryos. Fibroblasts derived from patients with congenital sialidosis (primary deficiency of neuraminidase-1) and galactosialidosis (secondary deficiency of neuraminidase-1) demonstrated impaired elastogenesis, which could be reversed after their transduction with neuraminidase-1 cDNA or after treatment with bacterial sialidase, which has a similar substrate specificity to human neuraminidase-1. We postulate that neuraminidase-1 catalyzes removal of the terminal sialic acids from carbohydrate chains of microfibrillar glycoproteins and other adjacent matrix glycoconjugates, unmasking their penultimate galactosugars. In turn, the exposed galactosugars interact with the galectin domain of EBP, thereby inducing the release of transported tropoelastin molecules and facilitating their subsequent assembly into elastic fibers.

          Related collections

          Author and article information

          Comments

          Comment on this article