Recombinant domain IV of perlecan binds to nidogens, laminin–nidogen complex, fibronectin, fibulin‐2 and heparin

• Published in: European journal of biochemistry Vol. 259; no. 3; pp. 917 - 926
• Main Authors: Hopf , Michael, Göhring, Walter, Kohfeldt, Eddie, Yamada, Yoshihiko, Timpl, Rupert
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.02.1999
• Subjects: Animals; Basement Membrane - metabolism; basement membranes; binding assays; Biosensing Techniques; Calcium-Binding Proteins - metabolism; Cell Line; Circular Dichroism; Extracellular Matrix Proteins - metabolism; Fibronectins - metabolism; Heparan Sulfate Proteoglycans; Heparin - metabolism; Heparitin Sulfate - chemistry; Heparitin Sulfate - genetics; Laminin - metabolism; Membrane Glycoproteins - metabolism; Mice; Microscopy, Electron; Peptide Fragments - metabolism; Peptide Fragments - ultrastructure; Protein Binding; proteoglycan structure; Proteoglycans - chemistry; Proteoglycans - genetics; Radioimmunoassay; recombinant production; Recombinant Proteins - metabolism
• DOI: 10.1046/j.1432-1327.1999.00127.x
• ISSN: 0014-2956

Domain IV of mouse perlecan, which consists of 14 immunoglobulin superfamily (IG) modules, was prepared from recombinant human cell culture medium in the form of two fragments, IV‐1 (IG2–9, 100 kDa) and IV‐2 (IG10–15, 66 kDa). Both fragments bound to a heparin column, being eluted at ionic strengths either below (IV‐2) or above (IV‐1) physiological level, and could thus be readily purified. Electron microscopy demonstrated an elongated shape (20–25 nm), and folding into a native structure was indicated by immunological assay and CD spectroscopy. Solid‐phase and surface plasmon resonance assays demonstrated strong binding of fragment IV‐1 to fibronectin, nidogen‐1, nidogen‐2 and the laminin‐1–nidogen‐1 complex, with Kd values in the range 4–17 n m. The latter binding apparently occurs through nidogen‐1, as shown by the formation of ternary complexes. Only moderate binding was observed for fibulin‐2 and collagen IV and none for fibulin‐1 and BM‐40. Fragment IV‐2 showed a more restricted pattern of binding, with only weaker binding to fibronectin and fibulin‐2. None of these activities could be demonstrated for recombinant fragments corresponding to the N‐terminal perlecan domains I to III. This indicates a special role for domain IV in the integration of perlecan into basement membranes and other extracellular structures via protein–protein interactions.