title: Testis-Specific GTPase (TSG): An oligomeric protein.
abstract: Ras-related proteins in brain (Rab)-family proteins are key members of the membrane trafficking pathway in cells. In addition, these proteins have been identified to have diverse functions such as cross-talking with different kinases and playing a role in cellular signaling. However, only a few Rab proteins have been found to have a role in male germ cell development. The most notable functions of this process are performed by numerous testis-specific and/or germ cell-specific genes. Here, we describe a new Rab protein that is specifically expressed in male germ cells, having GTPase activity.
  
  
  
  Testis-specific GTPase (TSG) is a male-specific protein that is highly expressed in the testis. It has an ORF of 1593 base pairs encoding a protein of 530 amino acids. This protein appears in testicular cells approximately 24 days postpartum and is maintained thereafter. Immunohistochemistry of testicular sections indicates localized expression in germ cells, particularly elongating spermatids. TSG has a bipartite nuclear localization signal that targets the protein to the nucleus. The C-terminal region of TSG contains the characteristic domain of small Rab GTPases, which imparts GTPase activity. At the N-terminal region, it has a coiled-coil motif that confers self-interaction properties to the protein and allows it to appear as an oligomer in the testis.
  
  
  
  TSG, being expressed in the male gonad in a developmental stage-specific manner, may have a role in male germ cell development. Further investigation of TSG function in vivo may provide new clues for uncovering the secrets of spermatogenesis.
authors.affiliation: Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea.
authors.forename: Sudeep
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Nursing, Dongkang College, Gwangju, Republic of Korea.
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea.
authors.forename: Hee-Sae
authors.initials: HS
authors.lastname: Park
authors.affiliation: Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea. klee@chonnam.ac.kr.
authors.forename: Keesook
authors.initials: K
authors.lastname: Lee
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D019556:COS Cells; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian; D004789:Enzyme Activation; D020558:GTP Phosphohydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D023061:Gene Order; D056426:Genetic Loci; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D051379:Mice; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D013737:Testis / Q000201:enzymology*
chemical_list: D009687:Nuclear Proteins; D020558:GTP Phosphohydrolases
keywords: GTPase; RASEF; Testis