title: Periostin promotes secretion of fibronectin from the endoplasmic reticulum.
abstract: Extracellular matrix (ECM) proteins are synthesized in the endoplasmic reticulum (ER), transported to the extracellular milieu through the secretory pathway, and assembled into an extracellular architecture. A previous study of ours showed that periostin, a secretory protein, interacts with fibronectin and is involved in ECM remodeling. Here we show that periostin played a role in fibronectin secretion from the ER. Co-immunoprecipitation and in situ proximity ligation assays revealed an interaction between periostin and fibronectin in the ER. Although accumulation of fibronectin was detected in the ER of fibroblastic C3H10T1/2 cells, forced expression of periostin in those cells decreased the accumulation of fibronectin in the ER, suggesting that periostin promoted the secretion of fibronectin. A substitution mutant of tryptophan at the position 65 to alanine in the EMI domain of periostin, which caused periostin to lose its ability to interact with fibronectin, did not decrease the accumulation. Furthermore, targeted disruption of periostin in mice caused the non-fibrillar and ectopic deposition of fibronectin in the periodontal ligament. Thus, these results demonstrate a subcellular role of periostin in promotion of fibronectin secretion from the ER.
authors.affiliation: Department of Biological Information, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan; Pathophysiological and Health Science Team, Imaging Application Group, Division of Bio-Function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan. Electronic address: isao.kii@riken.jp.
authors.forename: Isao
authors.initials: I
authors.lastname: Kii
authors.affiliation: Department of Biological Information, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishiyama
authors.affiliation: Department of Biological Information, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan. Electronic address: akudo@bio.titech.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Kudo
mesh_terms: D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D003238:Connective Tissue / Q000378:metabolism*; D004721:Endoplasmic Reticulum; D005109:Extracellular Matrix / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D015854:Up-Regulation / Q000502:physiology
chemical_list: D015815:Cell Adhesion Molecules; D005353:Fibronectins; C512835:POSTN protein, human
keywords: Endoplasmic reticulum; Fibronectin; Periodontal ligament; Periostin