title: Identification of KIAA1210 as a novel X-chromosome-linked protein that localizes to the acrosome and associates with the ectoplasmic specialization in testes.
abstract: Cell junctions are necessary for spermatogenesis, and there are numerous types of junctions in testis, such as blood–testis barrier, intercellular bridge, and ectoplasmic specialization (ES). The details of their functions and construction are still unknown. To identify a novel protein essential to the function of a cell junction, we enriched testis membrane protein and analyzed it using a proteomics approach. Here, we report a novel ES protein, which is encoded on the X chromosome and an ortholog of hypothetical human protein KIAA1210. KIAA1210 is expressed in testis predominantly, localized to the sex body in spermatocyte, acrosome, and near ES. Moreover, KIAA1210 possesses a topoisomerase 2 (TOP2)-associated protein PAT1 domain, a herpes simplex virus 1 (HSV-1) large tegument protein UL36 hypothetical domain, and a provisional DNA translocase FtsK domain. Using IP-proteomics with specific antibody to KIAA1210, we identified proteins including TOP2 isoforms as components of a complex with KIAA1210, in cell junctions in testis. The interaction between KIAA1210 and TOP2 was confirmed by two different proteomic analyses. Furthermore, immunofluorescence showed that KIAA1210 and TOP2B co-localize around the sex body in spermatocyte, apical ES, and residual bodies in elongated spermatids. Our findings suggest that KIAA1210 may be essential cell junction protein that interacts with TOP2B to regulate the dynamic change of chromatin structures during spermiogenesis.
authors.affiliation: Department of Biomedicine, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.|Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Tokuko
authors.initials: T
authors.lastname: Iwamori
authors.affiliation: Department of Biomedicine, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.|Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Iwamori
authors.affiliation: Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Department of Biomedicine, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.|Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Etsuro
authors.initials: E
authors.lastname: Ono
authors.affiliation: Departments of Pathology and Immunology, Molecular and Cellular Biology, Molecular and Human Genetics, and Pharmacology, Center for Drug Discovery, and Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Matzuk
mesh_terms: D000177:Acrosome / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology*; D050172:Genes, X-Linked / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D021381:Protein Transport; D013737:Testis / Q000502:physiology*
chemical_list: C000627521:Gm14569 protein, mouse; D008565:Membrane Proteins
keywords: KIAA1210; testis; ectoplasmic specialization; acrosome; topoisomerase II beta