title: [The apoptosis-inducing activity of human selenoprotein P shorter isoform].
abstract: OBJECTIVE
  Human selenoprotein P (HSelP) is unique protein that contains 10 selenocysteines encoded by 10 inframe UGA, which typically function as stop codon. The function of HSelP remains unclear, in part due to the inability to express it by gene recombinant technique. This study is to investigate expression and purification of recombinant HSelP in prokaryotic expression system, and its activity to induce apoptosis in vitro.
  
  
  METHODS
  The shorter HSelP isoform was cloned. After the selenocysteine (SeCys) at 40th position from N terminus of the HSelP shorter isoform was mutated into cysteine by PCR, it was expressed in E. coli. The expressed product was purified with DEAE column and identified by Western blot. Subsequently, its function on induction of mitochondrial apoptotic activity was studied.
  
  
  RESULTS
  The mutant HSelP shorter isoform expressed in prokaryotic system was purified by DEAE column to 90% homogeneity. The purified product, HSelP280m, induced the opening of mitochondrial permeability transition pore (PTP) and decreased the transmembrane potential in a dose-dependent manner. These events could be abolished by PTP specific inhibitors.
  
  
  CONCLUSIONS
  HSelP280m can induce the opening of mitochondrial PTP, which provides a basis for investigating the structure and function of recombinant HSelP.
authors.affiliation: Department of Molecular Oncology, Cancer Institute (Hospital), Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100021, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Fang
authors.forename: Yao
authors.initials: Y
authors.lastname: Yi
authors.forename: Yan-hua
authors.initials: YH
authors.lastname: Zheng
authors.forename: Quan
authors.initials: Q
authors.lastname: Chen
authors.forename: Li
authors.initials: L
authors.lastname: Ning
authors.forename: Yuan-yuan
authors.initials: YY
authors.lastname: Zha
authors.forename: Sheng-li
authors.initials: SL
authors.lastname: Bi
authors.forename: Jian-guo
authors.initials: JG
authors.lastname: Yang
authors.forename: Chen
authors.initials: C
authors.lastname: Lin
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D003001:Cloning, Molecular; D003545:Cysteine / Q000235:genetics; D004926:Escherichia coli / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000187:drug effects*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008930:Mitochondria, Liver / Q000502:physiology*; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D009154:Mutation; D020033:Protein Isoforms; D011506:Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D012643:Selenium; D017279:Selenocysteine / Q000235:genetics; D051149:Selenoprotein P; D051140:Selenoproteins
chemical_list: D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D020033:Protein Isoforms; D011506:Proteins; D051149:Selenoprotein P; D051140:Selenoproteins; D017279:Selenocysteine; D012643:Selenium; D003545:Cysteine