title: Regulation of FSHβ induction in LβT2 cells by BMP2 and an Activin A/BMP2 chimera, AB215.
abstract: Activins and bone morphogenetic proteins (BMPs) share activin type 2 signaling receptors but utilize different type 1 receptors and Smads. We designed AB215, a potent BMP2-like Activin A/BMP2 chimera incorporating the high-affinity type 2 receptor-binding epitope of Activin A. In this study, we compare the signaling properties of AB215 and BMP2 in HEK293T cells and gonadotroph LβT2 cells in which Activin A and BMP2 synergistically induce FSHβ. In HEK293T cells, AB215 is more potent than BMP2 and competitively blocks Activin A signaling, while BMP2 has a partial blocking activity. Activin A signaling is insensitive to BMP pathway antagonism in HEK293T cells but is strongly inhibited by constitutively active (CA) BMP type 1 receptors. By contrast, the potencies of AB215 and BMP2 are indistinguishable in LβT2 cells and although AB215 blocks Activin A signaling, BMP2 has no inhibitory effect. Unlike HEK293T, Activin A signaling is strongly inhibited by BMP pathway antagonism in LβT2 cells but is largely unaffected by CA BMP type 1 receptors. BMP2 increases phospho-Smad3 levels in LβT2 cells, in both the absence and the presence of Activin A treatment, and augments Activin A-induced FSHβ. AB215 has the opposite effect and sharply decreases basal phospho-Smad3 levels and blocks Smad2 phosphorylation and FSHβ induction resulting from Activin A treatment. These findings together demonstrate that while AB215 activates the BMP pathway, it has opposing effects to those of BMP2 on FSHβ induction in LβT2 cells apparently due to its ability to block Activin A signaling.
authors.affiliation: Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Jae Woo
authors.initials: JW
authors.lastname: Jung
authors.affiliation: Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Chihoon
authors.initials: C
authors.lastname: Ahn
authors.affiliation: Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Shim
authors.affiliation: Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Gray
authors.affiliation: Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Witek
authors.initials: W
authors.lastname: Kwiatkowski
authors.affiliation: Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA Joint Center for BiosciencesSongdo Global University Campus, 187 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaStructural Biology LaboratoryClayton Foundation Laboratories for Peptide BiologyThe Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA choe@salk.edu.
authors.forename: Senyon
authors.initials: S
authors.lastname: Choe
mesh_terms: D028341:Activins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D037201:Follicle Stimulating Hormone, beta Subunit / Q000235:genetics*; D052681:Gonadotrophs / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D055396:Bone Morphogenetic Protein 2; D037201:Follicle Stimulating Hormone, beta Subunit; D011993:Recombinant Fusion Proteins; D051899:Smad2 Protein; D051900:Smad3 Protein; C422405:activin A; D028341:Activins
keywords: activin; bone morphogenetic protein (BMP); protein structure; signal transduction; transforming growth factor beta (TGFβ)