title: Amino acid 72 of mouse and human GDF9 mature domain is responsible for altered homodimer bioactivities but has subtle effects on GDF9:BMP15 heterodimer activities.
abstract: Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are oocyte-secreted paralogs of the transforming growth factor beta (TGFbeta) superfamily. In mammals, these two growth factors play critical roles in folliculogenesis. As previously reported, an arginine in the pre-helix loop of GDF5 defines the high binding specificity to its type 1 receptor. Interestingly, bioactive mouse GDF9 and human BMP15 share the conserved arginine in the pre-helix loop, but their low-activity counterparts (mouse BMP15 and human GDF9) have a glycine or a proline instead. To address the question of whether the arginine residue defines the different activities of GDF9 and BMP15 homodimers and their heterodimers in human and mouse, we used site-directed mutagenesis to change the species-specific residues in human and mouse proteins, and examined their activities in our in vitro assays. Although amino acid 72 of mature GDF9 is responsible for altered homodimer bioactivities, neither the corresponding BMP15 amino acid 62 nor the intact pre-helix loop is indispensable for BMP15 homodimer activity. However, amino acid 72 in GDF9 only has only subtle effects on GDF9:BMP15 heterodimer activity. Based on previous studies and our recent findings, we provide hypothetical models to understand the molecular mechanism to define activities of the homodimeric and heterodimeric ligands. The arginine residue in the pre-helix loop of GDF9 homodimer may prevent the inhibition from its pro-domain or directly alter receptor binding, but this residue in GDF9 does not significantly affect the heterodimer activity, because of suggested conformational changes during heterodimer formation.
authors.affiliation: Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas.
authors.forename: Jia
authors.initials: J
authors.lastname: Peng
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine.
authors.forename: Karen
authors.initials: K
authors.lastname: Wigglesworth
authors.affiliation: Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas Deparment of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas.
authors.forename: Adithya
authors.initials: A
authors.lastname: Rangarajan
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine.
authors.forename: John J
authors.initials: JJ
authors.lastname: Eppig
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Thompson
authors.affiliation: Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas Deparment of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas Department of Pharmacology, Baylor College of Medicine, Houston, Texas Center for Drug Discovery, Baylor College of Medicine, Houston, Texas Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas mmatzuk@bcm.edu.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Matzuk
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D055430:Bone Morphogenetic Protein 15 / Q000378:metabolism*; D002478:Cells, Cultured; D005260:Female; D055429:Growth Differentiation Factor 9 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D011485:Protein Binding / Q000235:genetics; D054730:Protein Interaction Domains and Motifs / Q000235:genetics; D055503:Protein Multimerization / Q000235:genetics; D017433:Protein Structure, Secondary
chemical_list: C525901:BMP15 protein, human; C525902:Bmp15 protein, mouse; D055430:Bone Morphogenetic Protein 15; C525897:GDF9 protein, human; C525898:Gdf9 protein, mouse; D055429:Growth Differentiation Factor 9
keywords: follicular development; growth factors; ovary