title: Structural insight into Caenorhabditis elegans sex-determining protein FEM-2.
abstract: In the nematode Caenorhabditis elegans, fem-1, fem-2, and fem-3 play crucial roles in male sexual development. Among these three genes, fem-2 encodes a PP2C (serine/threonine phosphatase type 2C)-like protein, whose activity promotes the development of masculinity. Different from the canonical PP2Cs, FEM-2 consists of an additional N-terminal domain (NTD) apart from its C-terminal catalytic domain. Interestingly, genetic studies have indicated indispensable roles for both of these two domains of FEM-2 in promoting male development, but the underlying mechanism remains unknown. In the present study, we solved the crystal structure of full-length FEM-2, which revealed a novel structural fold formed by its NTD. Structural and functional analyses demonstrated that the NTD did not directly regulate the in vitro dephosphorylation activity of FEM-2, but instead functioned as a scaffold domain in the assembly of the FEM-1/2/3 complex, the executioner in the final step of the sex determination pathway. Biochemical studies further identified the regions in the NTD involved in FEM-1 and FEM-3 interactions. Our results not only identified a novel fold formed by the extra domain of a noncanonical PP2C enzyme, but also provided important insights into the molecular mechanism of how the NTD works in mediating the sex-determining role of FEM-1/2/3 complex.
authors.affiliation: Ministry of Education (MOE) Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhao
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Jingpeng
authors.initials: J
authors.lastname: Ge
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Jinke
authors.initials: J
authors.lastname: Gu
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.forename: Yue
authors.initials: Y
authors.lastname: Feng
authors.forename: Maojun
authors.initials: M
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D019849:Sex Determination Processes / Q000235:genetics*
chemical_list: D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; C115306:FEM-1 protein, C elegans; C075059:fem-3 protein, C elegans; C097435:Fem-2 protein, C elegans; D010749:Phosphoprotein Phosphatases
keywords: C. elegans; FEM-2; Novel Fold; Protein Phosphatase; Protein Structure; Sex Determination; Structural Biology; Substrate; X-ray Crystallography