title: Identification of fibronectin binding sites in dermatopontin and their biological function.
abstract: BACKGROUND
  Dermatopontin (DP) is a 22kDa acidic extracellular matrix (ECM) protein that plays a critical role in both ECM structure and wound healing. Previously, we demonstrated that DP interacts with fibronectin (Fn) and promotes formation of insoluble Fn fibrils that are called activated Fn (Kato et al., J Biol Chem 2011;286:14861-9).
  
  
  OBJECTIVE
  Details of the interaction between DP and Fn are investigated to further examine the biological functions of DP.
  
  
  METHODS
  Interactive sites between Fn and DP were examined by a solid-phase assay using Fn, DP, and their respective recombinant proteins and synthetic peptides. The effect of the DP peptides on insoluble Fn fibril formation was examined by both electrophoresis and electron microscopy.
  
  
  RESULTS
  A binding site in DP for Fn was identified as the DP-4 (PHGQVVVAVRS) peptide, and the major binding site in Fn for DP was the 14th type III repeat (III14) domain. Further, the major DP binding site in the III14 domain was located around the B- and C-strands and their connecting loop region. A synthetic cyclic peptide mimicking the Fn loop structure enhanced DP binding activity. The DP-4 peptide induced Fn polymerization but the morphology was different from that of Fn fibrils formed by full length DP. The Fn fibrils with DP-4 enhanced integrin α5β1-mediated cell adhesion and spreading.
  
  
  CONCLUSIONS
  Interactive sites between Fn and DP were identified. The DP-4 peptide activated Fn and enhanced cell adhesion activity. DP-4 has the potential to be used for therapeutic applications, such as a wound treatment.
authors.affiliation: Department of Plastic Surgery, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu-shi, Oita 879-5593, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Kato
authors.affiliation: Department of Dermatology, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu-shi, Oita 879-5593, Japan. Electronic address: ookamoto@oita-u.ac.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Okamoto
authors.affiliation: Department of Plastic Surgery, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu-shi, Oita 879-5593, Japan.
authors.forename: Weimin
authors.initials: W
authors.lastname: Wu
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu-shi, Oita 879-5593, Japan.
authors.forename: Noritaka
authors.initials: N
authors.lastname: Matsuo
authors.affiliation: Laboratory of Clinical Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kumai
authors.affiliation: Laboratory of Clinical Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Laboratory of Clinical Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Katagiri
authors.affiliation: Laboratory of Clinical Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Motoyoshi
authors.initials: M
authors.lastname: Nomizu
authors.affiliation: Department of Dermatology, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu-shi, Oita 879-5593, Japan.
authors.forename: Sakuhei
authors.initials: S
authors.lastname: Fujiwara
mesh_terms: D000818:Animals; D001665:Binding Sites; D011508:Chondroitin Sulfate Proteoglycans / Q000378:metabolism*; D004549:Elastin / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D020868:Gene Silencing; D006706:Homeostasis; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D015595:Skin Aging; D013844:Thiazoles / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D011508:Chondroitin Sulfate Proteoglycans; C082019:DPT protein, human; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; C425931:GW 501516; D039081:Integrin alpha5beta1; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D013844:Thiazoles; D004549:Elastin
keywords: Active peptide; Dermatopontin; Fibronectin; Wound healing