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Human immunodeficiency virus-1 recombinant gp120 induces changes in protein kinase C isozymes--a preliminary report
1Division of Basic and Clinical Immunology, University of California, Irvine 92717.
Insights
Human immunodeficiency virus 1 (HIV-1) gp120 protein activates protein kinase C (PKC) isozymes in U937 cells. This study reveals HIV-1 gp120 impacts both calcium-dependent and -independent PKC, notably PKC-zeta.
Area of Science:
- Immunology
- Cell Biology
- Virology
Background:
- Protein Kinase C (PKC) is crucial for cellular signaling.
- HIV-1 proteins, like gp120, can modulate host cell functions.
- Understanding HIV-1 interactions with cellular signaling pathways is vital.
Purpose of the Study:
- To investigate the effects of HIV-1 gp120 on specific protein kinase C (PKC) isozymes.
- To compare the impact of HIV-1 gp120 with phorbol ester (PMA) on PKC isozymes in monocytic U937 cells.
Main Methods:
- Utilized flow cytometry with isozyme-specific antibodies.
- Analyzed PKC isozyme expression in U937 cells stimulated with recombinant HIV-1 gp120 and PMA.
- Quantified changes in calcium-dependent and -independent PKC isozymes.
Main Results:
- U937 cells expressed all PKC isozymes except PKC-gamma.
- Both PMA and HIV-1 gp120 increased levels of various PKC isozymes.
- HIV-1 gp120 significantly affected calcium-independent PKC isozymes, particularly PKC-zeta.
Conclusions:
- HIV-1 gp120 influences multiple PKC isozymes in U937 cells.
- This is the first demonstration of HIV-1 gp120 affecting calcium-independent PKC isozymes.
- These findings contribute to understanding HIV-1's impact on host cell signaling.
Abstract:
Human immunodeficiency virus 1 (HIV-1) and its purified proteins activate target cell functions. Because protein kinase C (PKC) plays a crucial role in signal transduction and there is a molecular heterogeneity of PKC, we compared the effect of recombinant HIV-1 gp120 and phorbol ester (PMA) on PKC isozymes in monocytic U937 cells, with isozyme-specific antibodies using flow cytometry. All PKC isozymes except PKC-gamma were present in U937 cells. Both PMA and HIV-1 gp120 increased levels of calcium-dependent and -independent PKC isozymes. The most striking change was observed in PKC-zeta isozymes levels. This study for the first time demonstrates that HIV-1 gp120 affects calcium-independent PKC isozymes in U937 cells.
