The HIV Nef protein alters Ca(2+) signaling in myelomonocytic cells through SH3-mediated protein-protein interactions.
Human immunodeficiency virus Nef plays an important role in AIDS pathogenesis. In addition to the well known down-regulation of cell surface receptors (CD4, MHCI), Nef is able to alter cellular signaling. Of particular interest for this study is the ability of Nef to bind with a very high affinity to SH3 domains of myelomonocyte-specific protein-tyrosine kinases of the Src family (Src-like PTK). We have therefore investigated Ca(2+) signaling in HL60 cells retrovirally transduced with wild type Nef or with a Nef mutant deficient in the SH3-interacting proline-rich motif (Nef((PXXP)4(-))). In differentiated HL60 cells, Nef markedly altered cellular Ca(2+) signaling; the amount of intracellularly stored Ca(2+) was increased, and as a consequence, store-operated Ca(2+)-influx was decreased. This effect was not observed in undifferentiated HL60 cells or in CEM T-lymphocytes and correlated with the differentiation-induced up-regulation of Src-like PTK. The Nef effect on Ca(2+) signaling depended entirely on the integrity of its PXXP motif. The Src-like PTK p56/59(hck) co-immunoprecipitated with both Nef and with the inositol 1,4,5-trisphosphate receptor, providing a possible mechanistic link between the viral protein and intracellular Ca(2+) stores of the host cell. Collectively, our results demonstrate that the human immunodeficiency virus 1 Nef protein manipulates intracellular Ca(2+) stores through SH3-mediated interactions in myelomonocytic cells.
Foti
M
M
Department of Morphology, Geneva Medical School, University of Geneva, CH-1225 Geneva, Switzerland.
Cartier
L
L
Piguet
V
V
Lew
D P
DP
Carpentier
J L
JL
Trono
D
D
Krause
K H
KH
D002117:Calcitriol / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015693:Gene Products, nef / Q000378:metabolism*; D018922:HL-60 Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051572:Proto-Oncogene Proteins c-hck; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection; D018909:src Homology Domains / Q000235:genetics / Q000502:physiology*; D019061:src-Family Kinases / Q000378:metabolism
D002120:Calcium Channel Agonists; D004791:Enzyme Inhibitors; D015693:Gene Products, nef; D007476:Ionophores; D011518:Proto-Oncogene Proteins; D015759:Ionomycin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019284:Thapsigargin; D011505:Protein-Tyrosine Kinases; C496631:HCK protein, human; D051572:Proto-Oncogene Proteins c-hck; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases; D002117:Calcitriol; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; D004121:Dimethyl Sulfoxide