RESUMO
A cDNA encoding the human fur gene product was isolated from a human hepatoma cell line. The cDNA encodes a protein with significant amino acid sequence identity to the prokaryotic subtilisin family of serine proteases. More extensive sequence identity was found when the protein was compared with eukaryotic proteases such as PRB1 of Saccharomyces cerevisiae, and with PC2 and PC3, the only other known mammalian subtilisin-like proteases. In contrast to these proteins, however, the fur gene product shares a more extensive topographic and functional homology with the KEX2 endoprotease of S. cerevisiae. Each protease contains a signal peptide, a glycosylated extra cytoplasmic domain, a hydrophobic membrane-spanning region, and a short, hydrophilic "tail" sequence. As with KEX2, the expressed human protease was shown to cleave mammalian proproteins at their paired basic amino acid processing sites. We have, therefore, proposed the function-based acronym PACE (paired basic amino acid cleaving enzyme) for this prototypic mammalian proprotein processing enzyme.
Assuntos
Endopeptidases/genética , Genes , Subtilisinas/genética , Sequência de Aminoácidos , Diamino Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Southern Blotting , Carcinoma Hepatocelular , Linhagem Celular , Clonagem Molecular , DNA/genética , Éxons , Humanos , Íntrons , Neoplasias Hepáticas , Dados de Sequência Molecular , Poli A/genética , Poli A/isolamento & purificação , RNA/genética , RNA/isolamento & purificação , Splicing de RNA , RNA Mensageiro , Mapeamento por Restrição , Saccharomyces cerevisiae/genética , Homologia de Sequência do Ácido NucleicoRESUMO
Intracellular proteolytic processing of precursor polypeptides is an essential step in the maturation of many proteins, including plasma proteins, hormones, neuropeptides, and growth factors. Most frequently, propeptide cleavage occurs after paired basic amino acid residues. To date, no mammalian propeptide processing enzyme with such specificity has been purified or cloned and functionally characterized. We report the isolation and functional expression of a cDNA encoding a propeptide-cleaving enzyme from a human liver cell line. The encoded protein, called PACE (paired basic amino acid cleaving enzyme), has structural homology to the well-characterized subtilisin-like protease Kex2 from yeast. The functional specificity of PACE for mediating propeptide cleavage at paired basic amino acid residues was demonstrated by the enhancement of propeptide processing of human von Willebrand factor when coexpressed with PACE in COS-1 cells.
Assuntos
Proteínas de Membrana , Precursores de Proteínas/genética , Processamento de Proteína Pós-Traducional , Subtilisinas/genética , Fator de von Willebrand/genética , Sequência de Aminoácidos , Animais , Linhagem Celular , Clonagem Molecular , Furina , Expressão Gênica , Biblioteca Gênica , Humanos , Fígado , Dados de Sequência Molecular , Sondas de Oligonucleotídeos , Homologia de Sequência do Ácido Nucleico , TransfecçãoRESUMO
With the development of computed tomography, soft tissues and foreign body collections are distinguished with remarkable resolution. This distinction is particularly useful when examining desiccated human remains, both in construction of research strategies and when invasive procedure (i.e., traditional autopsies, needle biopsies, etc.) are not possible. Though the organs differ markedly from living tissue, it is possible to distinguish major organs with some certainty. One case study exhibited three separate pathological conditions which were not demonstrated with traditional radiological procedures.
