title: Homology of perforin to the ninth component of complement (C9).
abstract: Perforin is one of the cytolytic factors present in the cytoplasmic granules of mouse cytotoxic T lymphocytes and natural killer cells. We have determined the sequence of the N-terminal amino acids of perforin purified from a mouse natural killer cell line, and, by using oligonucleotide probes corresponding to the amino acid residues, we have identified a complementary DNA encoding perforin from the cDNA library of a mouse cytotoxic T lymphocyte clone. As predicted from the functional similarities between perforin and the ninth component of the serum cytolytic system, complement (C9) (refs 4-8), the deduced primary structure of perforin has homology with C9 at their respective functionally conserved regions. We find that perforin is only expressed in killer cell lines, and not in helper T lymphocytes or other tumour cells tested. Thus we have provided direct molecular evidence that a killer-cell-specific protein evolutionally linked to C9 is involved in cell-mediated cytolysis.
authors.affiliation: Department of Immunology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Shinkai
authors.forename: K
authors.initials: K
authors.lastname: Takio
authors.forename: K
authors.initials: K
authors.lastname: Okumura
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003186:Complement C9 / Q000235:genetics; D004247:DNA / Q000235:genetics; D006801:Humans; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D011499:Protein Processing, Post-Translational; D012689:Sequence Homology, Nucleic Acid; D013602:T-Lymphocytes, Cytotoxic / Q000032:analysis*; D014337:Trout
chemical_list: D003186:Complement C9; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D052899:Pore Forming Cytotoxic Proteins; D054353:Perforin; D004247:DNA