Crystal Structure of the Fibronectin 8-9FnI Domain Pair in Complex with a Type-I Collagen Peptide
[FINC_HUMAN] Defects in FN1 are the cause of glomerulopathy with fibronectin deposits type 2 (GFND2) [MIM:601894]; also known as familial glomerular nephritis with fibronectin deposits or fibronectin glomerulopathy. GFND is a genetically heterogeneous autosomal dominant disorder characterized clinically by proteinuria, microscopic hematuria, and hypertension that leads to end-stage renal failure in the second to fifth decade of life.
[FINC_HUMAN] Fibronectins bind cell surfaces and various compounds including collagen, fibrin, heparin, DNA, and actin. Fibronectins are involved in cell adhesion, cell motility, opsonization, wound healing, and maintenance of cell shape.    Anastellin binds fibronectin and induces fibril formation. This fibronectin polymer, named superfibronectin, exhibits enhanced adhesive properties. Both anastellin and superfibronectin inhibit tumor growth, angiogenesis and metastasis. Anastellin activates p38 MAPK and inhibits lysophospholipid signaling.   
Publication Abstract from PubMed
Collagen and fibronectin are major components of vertebrate extracellular matrices. Their association and distribution control the development and properties of diverse tissues, but thus far no structural information has been available for the complex formed. Here, we report binding of a peptide, derived from the alpha(1) chain of type I collagen, to the gelatin-binding domain of human fibronectin and present the crystal structure of this peptide in complex with the (8-9)FnI domain pair. Both gelatin-binding domain subfragments, (6)FnI(1-2)FnII(7)FnI and (8-9)FnI, bind the same specific sequence on D-period 4 of collagen I alpha(1), adjacent to the MMP-1 cleavage site. (8-9)FnI also binds the equivalent sequence of the alpha(2) chain. The collagen peptide adopts an antiparallel beta-strand conformation, similar to structures of proteins from pathogenic bacteria bound to FnI domains. Analysis of the type I collagen sequence suggests multiple putative fibronectin-binding sites compatible with our structural model. We demonstrate, by kinetic unfolding experiments, that the triple-helical collagen state is destabilized by (8-9)FnI. This finding suggests a role for fibronectin in collagen proteolysis and tissue remodeling.
Identification and structural analysis of type I collagen sites in complex with fibronectin fragments.,Erat MC, Slatter DA, Lowe ED, Millard CJ, Farndale RW, Campbell ID, Vakonakis I Proc Natl Acad Sci U S A. 2009 Mar 17;106(11):4195-200. Epub 2009 Feb 27. PMID:19251642
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.