title: Stepwise assembly of fibrinogen is assisted by the endoplasmic reticulum lectin-chaperone system in HepG2 cells.
abstract: The endoplasmic reticulum (ER) plays essential roles in protein folding and assembly of secretory proteins. ER-resident molecular chaperones and related enzymes assist in protein maturation by co-operated interactions and modifications. However, the folding/assembly of multimeric proteins is not well understood. Here, we show that the maturation of fibrinogen, a hexameric secretory protein (two trimers from α, β and γ subunits), occurs in a stepwise manner. The αγ complex, a precursor for the trimer, is retained in the ER by lectin-like chaperones, and the β subunit is incorporated into the αγ complex immediately after translation. ERp57, a protein disulfide isomerase homologue, is involved in the hexamer formation from two trimers. Our results indicate that the fibrinogen hexamer is formed sequentially, rather than simultaneously, using kinetic pause by lectin chaperones. This study provides a novel insight into the assembly of most abundant multi-subunit secretory proteins.
authors.affiliation: Department of Cell Science, Institute of Biomedical Sciences, Fukushima Medical University, Fukushima, Japan ; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (JST), Tokyo, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Tamura
authors.forename: Seisuke
authors.initials: S
authors.lastname: Arai
authors.forename: Hisao
authors.initials: H
authors.lastname: Nagaya
authors.forename: Jun
authors.initials: J
authors.lastname: Mizuguchi
authors.forename: Ikuo
authors.initials: I
authors.lastname: Wada
mesh_terms: D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005340:Fibrinogen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D007700:Kinetics; D018832:Molecular Chaperones / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D019704:Protein Disulfide-Isomerases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017510:Protein Folding; D055503:Protein Multimerization; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism
chemical_list: C485182:Cyan Fluorescent Protein; D018832:Molecular Chaperones; D021122:Protein Subunits; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; D005340:Fibrinogen; D019704:Protein Disulfide-Isomerases; C085868:PDIA3 protein, human
references.citation: J Biol Chem. 2006 Jan 13;281(2):876-84
references.pmid: 16368681
references.citation: J Biol Chem. 2004 Oct 22;279(43):44600-5
references.pmid: 15308654
references.citation: Glycobiology. 2003 Sep;13(9):77R-91R
references.pmid: 12736198
references.citation: J Biol Chem. 2004 May 14;279(20):21533-42
references.pmid: 14976197
references.citation: J Biol Chem. 1996 Nov 1;271(44):27942-7
references.pmid: 8910396
references.citation: Semin Cell Dev Biol. 2010 Jul;21(5):512-9
references.pmid: 20044014
references.citation: Curr Opin Struct Biol. 1998 Dec;8(6):792-8
references.pmid: 9914253
references.citation: EMBO J. 1995 Sep 1;14(17):4196-203
references.pmid: 7556060
references.citation: J Thromb Haemost. 2005 Aug;3(8):1894-904
references.pmid: 16102057
references.citation: Biochim Biophys Acta. 2003 Jun 17;1641(1):1-12
references.pmid: 12788224
references.citation: Eur J Biochem. 1998 Aug 15;256(1):51-9
references.pmid: 9746345
references.citation: Ann N Y Acad Sci. 2001;936:480-95
references.pmid: 11460506
references.citation: Traffic. 2000 Jul;1(7):533-9
references.pmid: 11208140
references.citation: J Biol Chem. 1992 Nov 15;267(32):23151-8
references.pmid: 1429662
references.citation: Proc Natl Acad Sci U S A. 2000 Jun 20;97(13):7290-5
references.pmid: 10852971
references.citation: Ann N Y Acad Sci. 2003 Sep;998:66-80
references.pmid: 14592864
references.citation: Annu Rev Biochem. 2011;80:71-99
references.pmid: 21495850
references.citation: J Biol Chem. 1993 Apr 25;268(12):8919-26
references.pmid: 8473334
references.citation: EMBO J. 2001 Nov 15;20(22):6288-96
references.pmid: 11707400
references.citation: EMBO Rep. 2002 Feb;3(2):136-40
references.pmid: 11839698
references.citation: Science. 1999 Dec 3;286(5446):1882-8
references.pmid: 10583943
references.citation: J Biochem. 1999 Dec;126(6):1090-100
references.pmid: 10578061
references.citation: J Biol Chem. 2009 Apr 10;284(15):10160-73
references.pmid: 19196713
references.citation: Trends Biochem Sci. 2003 Jan;28(1):49-57
references.pmid: 12517452
references.citation: FEBS J. 2008 Oct;275(19):4700-27
references.pmid: 18680510
references.citation: J Biol Chem. 2002 Nov 22;277(47):44838-44
references.pmid: 12239218
references.citation: Mol Biol Cell. 2010 Apr 1;21(7):1305-13
references.pmid: 20130085
references.citation: J Biol Chem. 1983 Nov 25;258(22):13407-10
references.pmid: 6315695
references.citation: Mol Biol Cell. 1999 Aug;10(8):2573-82
references.pmid: 10436013
references.citation: EMBO J. 1997 Sep 1;16(17):5420-32
references.pmid: 9312001
references.citation: J Biol Chem. 1996 Oct 4;271(40):24544-50
references.pmid: 8798716
references.citation: J Biol Chem. 1994 Jan 7;269(1):652-8
references.pmid: 8276866
references.citation: J Biol Chem. 1998 Mar 13;273(11):6009-12
references.pmid: 9497314
references.citation: J Biol Chem. 1991 Apr 5;266(10):6578-85
references.pmid: 1826107
references.citation: FEBS Lett. 2002 Feb 27;513(2-3):153-8
references.pmid: 11904141
references.citation: J Biol Chem. 2004 Sep 17;279(38):39872-9
references.pmid: 15254031
references.citation: J Biol Chem. 1984 Aug 25;259(16):10574-81
references.pmid: 6088505
references.citation: Cell. 1995 May 5;81(3):425-33
references.pmid: 7736594
references.citation: J Cell Biol. 1998 May 4;141(3):637-46
references.pmid: 9566965