title: BMP2 protein regulates osteocalcin expression via Runx2-mediated Atf6 gene transcription.
abstract: Bone morphogenetic protein 2 (BMP2) activates unfolded protein response (UPR) transducers, such as PERK and OASIS, in osteoblast cells. ATF6, a bZIP transcription factor, is also a UPR transducer. However, the involvement of ATF6 in BMP2-induced osteoblast differentiation has not yet been elucidated. In the present study, BMP2 treatment was shown to markedly induce the expression and activation of ATF6 with an increase in alkaline phosphatase (ALP) and OC expression in MC3T3E1 cells. In contrast, ATF6 activation by BMP2 was not observed in the Runx2(-/-) primary calvarial osteoblasts, and Runx2 overexpression recovered BMP2 action. BMP2 stimulated ATF6 transcription by enhancing the direct binding of Runx2 to the osteoblast-specific cis-acting element 2 (OSE2, ACCACA, -205 to -200 bp) motif of the Atf6 promoter region. In addition, the overexpression of ATF6 increased the Oc promoter activity by enhancing the direct binding to a putative ATF6 binding motif (TGACGT, -1126 to -1121 bp). The inhibition of ATF6 function with the dominant negative form of ATF6 (DN-ATF6) blocked BMP2- or Runx2-induced OC expression. Interestingly, OASIS, which is structurally similar to ATF6, did not induce Oc expression. ALP and Alizarin red staining results confirmed that BMP2-induced matrix mineralization was also dependent on ATF6 in vitro. Overall, these results suggest that BMP2 induces osteoblast differentiation through Runx2-dependent ATF6 expression, which directly regulates Oc transcription.
authors.affiliation: Dental Science Research Institute and BK21, School of Dentistry, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Won-Gu
authors.initials: WG
authors.lastname: Jang
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Kim
authors.forename: Don-Kyu
authors.initials: DK
authors.lastname: Kim
authors.forename: Hyun-Mo
authors.initials: HM
authors.lastname: Ryoo
authors.forename: Keun-Bae
authors.initials: KB
authors.lastname: Lee
authors.forename: Sun-Hun
authors.initials: SH
authors.lastname: Kim
authors.forename: Hueng-Sik
authors.initials: HS
authors.lastname: Choi
authors.forename: Jeong-Tae
authors.initials: JT
authors.lastname: Koh
mesh_terms: D051702:Activating Transcription Factor 6 / Q000235:genetics / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D015675:Osteocalcin / Q000096:biosynthesis* / Q000235:genetics; D020218:Response Elements / Q000502:physiology; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: C497111:ATF6 protein, human; D051702:Activating Transcription Factor 6; C497112:Atf6 protein, mouse; C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; C485618:CREB3L1 protein, human; D050659:Core Binding Factor Alpha 1 Subunit; C119923:Creb3l1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D009419:Nerve Tissue Proteins; C493709:RUNX2 protein, human; C493716:Runx2 protein, mouse; D015675:Osteocalcin; D000469:Alkaline Phosphatase
references.citation: J Cell Biochem. 1997 Jul 1;66(1):1-8
references.pmid: 9215522
references.citation: EMBO Rep. 2011 May;12(5):451-7
references.pmid: 21415858
references.citation: Biochem Biophys Res Commun. 2011 Jan 28;404(4):1004-9
references.pmid: 21187071
references.citation: Mol Cell Biol. 2004 Oct;24(20):8847-61
references.pmid: 15456860
references.citation: Biochem Biophys Res Commun. 2002 Apr 26;293(1):470-7
references.pmid: 12054625
references.citation: J Cell Physiol. 2008 Dec;217(3):693-707
references.pmid: 18683826
references.citation: EMBO J. 2005 Sep 7;24(17):3049-56
references.pmid: 16079911
references.citation: Endocr Rev. 2000 Aug;21(4):393-411
references.pmid: 10950158
references.citation: J Biol Chem. 2000 Sep 1;275(35):27013-20
references.pmid: 10856300
references.citation: Nature. 2002 Jan 3;415(6867):92-6
references.pmid: 11780124
references.citation: Genes Dev. 1998 Jun 15;12(12):1812-24
references.pmid: 9637683
references.citation: Cell. 1997 May 30;89(5):747-54
references.pmid: 9182762
references.citation: Endocrinology. 2008 Aug;149(8):3832-41
references.pmid: 18450959
references.citation: Mol Endocrinol. 1997 Oct;11(11):1695-708
references.pmid: 9328351
references.citation: Mol Cell Biol. 1995 Apr;15(4):1858-69
references.pmid: 7891679
references.citation: Brain Res Mol Brain Res. 1999 May 21;69(1):93-103
references.pmid: 10350641
references.citation: Mol Cell Biol. 2000 Sep;20(18):6755-67
references.pmid: 10958673
references.citation: Nat Cell Biol. 2009 Oct;11(10):1205-11
references.pmid: 19767743
references.citation: Mol Cell. 2000 Dec;6(6):1355-64
references.pmid: 11163209
references.citation: Biochem J. 2008 Aug 1;413(3):559-69
references.pmid: 18459945
references.citation: Cell. 2004 Apr 30;117(3):387-98
references.pmid: 15109498
references.citation: Bone Miner. 1994 Aug;26(2):109-22
references.pmid: 7994183
references.citation: J Mol Endocrinol. 2006 Jun;36(3):531-46
references.pmid: 16720721
references.citation: J Biol Chem. 2005 Sep 2;280(35):30689-96
references.pmid: 16000305
references.citation: J Cell Biochem. 1993 Jun;52(2):206-19
references.pmid: 8366137
references.citation: J Biol Chem. 2003 Sep 5;278(36):34387-94
references.pmid: 12815054
references.citation: Clin Calcium. 2006 May;16(5):801-7
references.pmid: 16679622
references.citation: Mol Cell Biol. 2001 Apr;21(8):2891-905
references.pmid: 11283267
references.citation: Dev Cell. 2002 Jul;3(1):99-111
references.pmid: 12110171
references.citation: Endocr Rev. 2003 Apr;24(2):218-35
references.pmid: 12700180
references.citation: Genes Dev. 1999 Apr 15;13(8):1025-36
references.pmid: 10215629
references.citation: J Endocrinol. 2001 Sep;170(3):667-75
references.pmid: 11524248
references.citation: J Cell Biochem. 2006 Dec 1;99(5):1233-9
references.pmid: 16795049
references.citation: J Bone Miner Res. 1998 Sep;13(9):1483-90
references.pmid: 9738522
references.citation: Mol Biol Cell. 1999 Nov;10(11):3787-99
references.pmid: 10564271
references.citation: Nature. 1999 Jan 21;397(6716):271-4
references.pmid: 9930704
references.citation: Cell. 1997 May 30;89(5):755-64
references.pmid: 9182763
references.citation: J Biol Chem. 2011 Feb 11;286(6):4809-18
references.pmid: 21135100
references.citation: J Biol Chem. 1998 Dec 11;273(50):33741-9
references.pmid: 9837962