title: Structural characterization and subcellular localization of Drosophila organic solute carrier partner 1.
abstract: BACKGROUND
  Organic solute carrier partner 1 (OSCP1) is known to facilitate the transport of various organic solutes into cells and reported to play a role in cell growth and cell differentiation. Moreover, OSCP1 is known as a tumor suppressor gene that is frequently down-expressed in nasopharyngeal carcinomas and acute myeloid leukemia. However, the underlying mechanisms of action remain unclear and the subcellular localization of OSCP1 has yet to be determined in detail.
  
  
  RESULTS
  Drosophila contains a single orthologue of OSCP1 (dOSCP1) that shares 58% homology with its human counterpart. To study the expression pattern and subcellular localization of dOSCP1, we prepared a specific antibody. Subcellular localization analyses of dOSCP1 with these revealed localization in the plasma membrane, endoplasmic reticulum, Golgi apparatus and mitochondria, but no detection in cytosol. dOSCP1 signals were also detected in the nucleus, although at weaker intensity than in plasma membranes and subcellular organelles. In addition, native polyacrylamide gel electrophoresis analysis with and without β-mercaptoethanol treatment revealed that recombinant dOSCP1 forms dimers and trimers in solution. The dimer form of dOSCP1 could also be detected by Western immunoblot analyses in third instar larval extracts.
  
  
  CONCLUSIONS
  The data revealed that dOSCP1 localizes not only in the plasma membrane but also in the nucleus, ER, Golgi apparatus and mitochondria. It is therefore conceivable that this protein may interact with various partners or form multimeric complexes with other proteins to play multiple roles in cells, providing clues to understanding the functions of dOSCP1 during Drosophila development.
authors.forename: Nguyen Tho
authors.initials: NT
authors.lastname: Huu
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Takanari
authors.initials: T
authors.lastname: Umegawachi
authors.forename: Seiji
authors.initials: S
authors.lastname: Miyata
authors.affiliation: Department of Applied Biology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan. myamaguc@kit.ac.jp.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D019281:Dimerization; D004330:Drosophila / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007814:Larva; D026901:Membrane Transport Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015394:Molecular Structure; D010802:Phylogeny; D021381:Protein Transport; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D059467:Transcriptome
chemical_list: D029721:Drosophila Proteins; D026901:Membrane Transport Proteins; C000593126:OSCP1 protein, Drosophila; C479458:OSCP1 protein, human; D011994:Recombinant Proteins