       Document 0591
 DOCN  M9460591
 TI    HIV-1 Nef inhibits a common activation pathway in NIH-3T3 cells.
 DT    9404
 AU    De SK; Marsh JW; Laboratory of Molecular Biology, National Institute of
       Mental; Health, Bethesda, Maryland 20892.
 SO    J Biol Chem. 1994 Mar 4;269(9):6656-60. Unique Identifier : AIDSLINE
       MED/94165057
 AB    The human immunodeficiency virus type 1 (HIV-1) Nef is a myristylated
       27-kDa, cytoplasmic protein. It is attributed to have suppressive
       effects on LTR-based expression and T cell activation. Additionally, SIV
       nef has been shown to possess an essential in vivo function in the
       development of immunodeficiency. To define the biochemical activity of
       HIV-1 Nef in a signal transduction pathway, we have transduced murine
       NIH-3T3 cells with a retroviral nef expression system. In nef-expressing
       cells, but not in controls, the proliferative response to bombesin and
       platelet-derived growth factor (PDGF) was eliminated. Analysis of an
       early signal pathway metabolite, inositol 1,4,5-trisphosphate, following
       bombesin and PDGF treatment to quiscent cells, revealed that both
       control and nef-transformed cells displayed similar kinetics of signal
       formation. Normally, inositol 1,4,5-trisphosphate mediates increase in
       the cytosolic free Ca2+ ([Ca2+]i). Upon stimulation with bombesin or
       PDGF, control cells displayed a 2-4-fold increase of [Ca2+]i over the
       basal level, while the [Ca2+]i response in nef-expressing NIH-3T3 cells
       was lacking or highly diminished. However, the release of [Ca2+]i from
       the intracellular store of the nef-expressing cells by an endomembrane
       Ca2+ ATPase inhibitor, thapsigargin, revealed that these cells contained
       normal Ca2+ stores. These results suggest a specific, definable
       biochemical activity for the HIV-1 Nef protein in the context of a well
       characterized cellular activation pathway. Our results thus define, for
       the first time, a unique function of Nef that is not limited to an
       alteration of T cell function or of expression of a T cell surface
       antigen.
 DE    Animal  Bombesin/PHARMACOLOGY  Calcium/*METABOLISM  Cytosol/METABOLISM
       DNA Replication/DRUG EFFECTS  Gene Products,
       nef/BIOSYNTHESIS/*METABOLISM  Genes, nef  Genetic Vectors
       HIV-1/GENETICS/*METABOLISM  Inositol 1,4,5-Trisphosphate/*METABOLISM
       Kinetics  Methionine/METABOLISM  Mice  Moloney Leukemia Virus
       Phosphotransferases (Alcohol Group Acceptor)/BIOSYNTHESIS
       Platelet-Derived Growth Factor/PHARMACOLOGY  RNA,
       Messenger/BIOSYNTHESIS/METABOLISM  Transduction, Genetic  Transfection
       3T3 Cells  JOURNAL ARTICLE

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

