HIV infection in vitro enhances the activity of src-family protein tyrosine kinases.
OBJECTIVE
We examined the effect of HIV infection on src-family protein tyrosine kinase (PTK) activity to determine if alterations in src-family PTK activity could contribute to the HIV-related chronic immune system activation observed in patients infected with HIV.


METHODS
Jurkat, a CD4+ human T lymphocyte cell line was infected with HIV IIIB. Kinase activity was determined by in vitro immune complex kinase assays using antibodies specific for the src-family PTKs, p56lck, p59fyn and p60c-src expressed in T lymphocytes. PTK protein and total phosphotyrosine levels were assessed by Western blotting. The role of the gp120-CD4-Lck interaction in HIV-related PTK activation was determined using gp 120-treated Jurkat cells and HIV-infection of JCaM 1.6 cells, a Jurkat-derived cell line that lacks p56lck.


RESULTS
Cells infected with HIV for 24 h exhibited increased levels of total tyrosine phosphorylation and enhanced src-family PTK activity without altered levels of expression of src-family kinases. The activity of Lck and Fyn was enhanced within 30 min of infection. HIV-related src-family PTK activation was not a function of the gp120-CD4-Lck interaction and occurred in the presence of 10 mmol/l zidovudine indicating that reverse transcriptase and activation of the HIV genome is not required.


CONCLUSIONS
HIV-related activation of src-family PTK is a response of the cell to early stages of the virus life cycle, possibly either membrane fusion or viral uncoating. These results indicate that endogenous src-family PTKs may play a role in HIV-related immune activation and dysfunction. Moreover, activation of src-family PTK may be a mechanism used by the virus to facilitate some aspect of its own life cycle.
Phipps
D J
DJ
Department of Oncology Research, Toronto Hospital, Canada.
Read
S E
SE
Piovesan
J P
JP
Mills
G B
GB
Branch
D R
DR
D002384:Catalysis; D004789:Enzyme Activation; D015699:HIV Envelope Protein gp120 / Q000378:metabolism; D054303:HIV Reverse Transcriptase / Q000378:metabolism; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D019000:Phosphotyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism*
D015699:HIV Envelope Protein gp120; D019000:Phosphotyrosine; D019061:src-Family Kinases; D054303:HIV Reverse Transcriptase