       Document 0679
 DOCN  M9630679
 TI    Calcium requirement and inhibitor spectrum for intracellular HIV type 1
       gp160 processing in cultured HeLa cells and CD4+ lymphocytes: similarity
       to those of viral envelope glycoprotein maturase.
 DT    9603
 AU    Kamoshita K; Shiota M; Sasaki M; Koga Y; Okumura Y; Kido H; Division of
       Enzyme Chemistry, University of Tokushima.
 SO    J Biochem (Tokyo). 1995 Jun;117(6):1244-53. Unique Identifier : AIDSLINE
       MED/96104996
 AB    We recently purified the calcium-independent processing protease named
       viral envelope glycoprotein maturase (VEM), that converts human
       immunodeficiency virus type 1 (HIV-1) envelope glycoprotein precursor
       gp160 to gp120 and gp41, from the human CD4+ T cell line, Molt-4 clone 8
       [Kido, H., Kamoshita, K., Fukutomi, A., and Katunuma, N. (1993) J. Biol.
       Chem. 268, 13406-13413]. In this report, we deal with the inhibitor
       specificity and calcium requirement for intracellular gp160 processing
       in cultured HeLa cells and human CD4+ lymphocytes. Processing of gp160
       in these cells infected with recombinant vaccinia virus encoding the
       gp160 gene was not affected by intracellular calcium depletion induced
       by the calcium ionophore A23187 and EGTA or by intracellular calcium
       administration. Processing of gp160 by the purified VEM in vitro was not
       inhibited by EDTA, EGTA, or the metallo-protease inhibitor
       phosphoramidon, but was specifically inhibited by a substrate analog,
       decanoyl-RVKR-chloromethylketone, and the trypsin-type protease
       inhibitors aprotinin, HI-30, and diisopropyl fluorophosphate (DFP). It
       was also inhibited by E-64 and thiol reagents. But intracellular gp160
       processing was inhibited only by permeable, low molecular mass
       inhibitors of VEM, such as DFP, E-64, and thiol reagents. Syncytium
       formation induced by cell surface gp120 was also inhibited by permeable
       inhibitors of VEM. Taken together, our results indicate that calcium
       ions may not be essential for intracellular gp160 processing and so
       HIV-1 gp160 induced by recombinant vaccinia virus may be processed
       mainly by a protease(s) that does not require calcium ions, such as VEM
       in these cells.
 DE    Amino Acid Sequence  Aniline Compounds  Calcimycin/PHARMACOLOGY
       Calcium/*METABOLISM/PHARMACOLOGY  CD4-Positive T-Lymphocytes/*METABOLISM
       Egtazic Acid/PHARMACOLOGY  Fluorescent Dyes  Gene Products,
       env/GENETICS/*METABOLISM  Giant Cells/METABOLISM  Glycoside
       Hydrolases/METABOLISM  Hela Cells  Human  *HIV-1/GENETICS  Kinetics
       Microscopy, Phase-Contrast  Molecular Sequence Data  Peptide
       Peptidohydrolases/*METABOLISM  Protease
       Inhibitors/CHEMISTRY/PHARMACOLOGY  Protein
       Precursors/GENETICS/*METABOLISM  *Protein Processing, Post-Translational
       Recombinant Proteins/METABOLISM  Sulfhydryl Reagents/PHARMACOLOGY
       Support, Non-U.S. Gov't  Vaccinia Virus  Xanthenes  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

