Simian immunodeficiency virus and human immunodeficiency virus type 1 nef proteins show distinct patterns and mechanisms of Src kinase activation.
The nef gene from human and simian immunodeficiency viruses (HIV and SIV) regulates cell function and viral replication, possibly through binding of the nef product to cellular proteins, including Src family tyrosine kinases. We show here that the Nef protein encoded by SIVmac239 interacts with and also activates the human Src kinases Lck and Hck. This is in direct contrast to the inhibitory effect of HIV type 1 (HIV-1) Nef on Lck catalytic activity. Unexpectedly, however, the interaction of SIV Nef with human Lck or Hck is not mediated via its consensus proline motif, which is known to mediate HIV-1 Nef binding to Src homology 3 (SH3) domains, and various experimental analyses failed to show significant interaction of SIV Nef with the SH3 domain of either kinase. Instead, SIV Nef can bind Lck and Hck SH2 domains, and its N-terminal 50 amino acid residues are sufficient for Src kinase binding and activation. Our results provide evidence for multiple mechanisms by which Nef binds to and regulates Src kinases.
Greenway
A L
AL
AIDS Cellular Biology Unit, Macfarlane Burnet Center for Medical Research, Fairfield, Victoria 3078, Australia.
Dutartre
H
H
Allen
K
K
McPhee
D A
DA
Olive
D
D
Collette
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D004789:Enzyme Activation; D015693:Gene Products, nef / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism*; D008969:Molecular Sequence Data; D010770:Phosphotransferases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051572:Proto-Oncogene Proteins c-hck; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015302:Simian Immunodeficiency Virus / Q000378:metabolism*; D054311:nef Gene Products, Human Immunodeficiency Virus; D018909:src Homology Domains
D015693:Gene Products, nef; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D054311:nef Gene Products, Human Immunodeficiency Virus; D010770:Phosphotransferases; D011505:Protein-Tyrosine Kinases; C496631:HCK protein, human; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051572:Proto-Oncogene Proteins c-hck