title: Structural and biochemical insights into the role of testis-expressed gene 14 (TEX14) in forming the stable intercellular bridges of germ cells.
abstract: Intercellular bridges are a conserved feature of spermatogenesis in mammalian germ cells and derive from arresting cell abscission at the final stage of cytokinesis. However, it remains to be fully understood how germ cell abscission is arrested in the presence of general cytokinesis components. The TEX14 (testis-expressed gene 14) protein is recruited to the midbody and plays a key role in the inactivation of germ cell abscission. To gain insights into the structural organization of TEX14 at the midbody, we have determined the crystal structures of the EABR [endosomal sorting complex required for transport (ESCRT) and ALIX-binding region] of CEP55 bound to the TEX14 peptide (or its chimeric peptides) and performed functional characterization of the CEP55-TEX14 interaction by multiexperiment analyses. We show that TEX14 interacts with CEP55-EABR via its AxGPPx3Y (Ala793, Gly795, Pro796, Pro797, and Tyr801) and PP (Pro803 and Pro804) sequences, which together form the AxGPPx3YxPP motif. TEX14 competitively binds to CEP55-EABR to prevent the recruitment of ALIX, which is a component of the ESCRT machinery with the AxGPPx3Y motif. We also demonstrate that a high affinity and a low dissociation rate of TEX14 to CEP55, and an increase in the local concentration of TEX14, cooperatively prevent ALIX from recruiting ESCRT complexes to the midbody. The action mechanism of TEX14 suggests a scheme of how to inactivate the abscission of abnormal cells, including cancer cells.
authors.affiliation: Department of Bio & Nano Chemistry, Kookmin University, Seoul 136-702, Korea;
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea;
authors.forename: Jungbin
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Department of Bio & Nano Chemistry, Kookmin University, Seoul 136-702, Korea;
authors.forename: Atsushi
authors.initials: A
authors.lastname: Matsuura
authors.affiliation: Department of Bio & Nano Chemistry, Kookmin University, Seoul 136-702, Korea;
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Na
authors.affiliation: Department of Bio & Nano Chemistry, Kookmin University, Seoul 136-702, Korea;
authors.forename: Won-Kyu
authors.initials: WK
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Kwangwoon University, Seoul 139-701, Korea;
authors.forename: Hyunook
authors.initials: H
authors.lastname: Kim
authors.affiliation: Biomolecular Function Research Branch, Division of Convergence Technology, National Cancer Center, Goyang, Gyeonggi 416-769, Korea;
authors.forename: Ji Woong
authors.initials: JW
authors.lastname: Choi
authors.affiliation: College of Pharmacy, Gachon University, Incheon 406-799, Korea;
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Park
authors.affiliation: College of Pharmacy, Gachon University, Incheon 406-799, Korea;
authors.forename: Sung-Jean
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Molecular Epidemiology Branch, Division of Cancer Epidemiology and Prevention, National Cancer Center, Goyang, Gyeonggi 416-769, Korea;
authors.forename: Kyung Tae
authors.initials: KT
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Kwangwoon University, Seoul 139-701, Korea;
authors.forename: Rakwoo
authors.initials: R
authors.lastname: Chang
authors.affiliation: Biomolecular Function Research Branch, Division of Convergence Technology, National Cancer Center, Goyang, Gyeonggi 416-769, Korea;
authors.forename: Byung Il
authors.initials: BI
authors.lastname: Lee
authors.affiliation: Department of Bio & Nano Chemistry, Kookmin University, Seoul 136-702, Korea;
authors.forename: Yeon Gyu
authors.initials: YG
authors.lastname: Yu
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korean Institute of Science and Technology, Seoul 136-791, Korea; Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011;
authors.forename: Yeon-Kyun
authors.initials: YK
authors.lastname: Shin
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korean Institute of Science and Technology, Seoul 136-791, Korea;
authors.forename: Cherlhyun
authors.initials: C
authors.lastname: Jeong
authors.affiliation: Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea;
authors.forename: Kunsoo
authors.initials: K
authors.lastname: Rhee
authors.affiliation: Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea hyungholee@snu.ac.kr.
authors.forename: Hyung Ho
authors.initials: HH
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D015870:Gene Expression; D005854:Germ Cells / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008810:Mice, Inbred C57BL; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013091:Spermatogenesis / Q000235:genetics; D013737:Testis / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; C505378:Cep55 protein, human; D009687:Nuclear Proteins; C548797:TEX14 protein, human; C510086:TEX14 protein, mouse; D014157:Transcription Factors
keywords: CEP55; TEX14; cytokinesis; germ cells; intercellular bridges