Article

Iκκ mediates NF-κB activation in human immunodeficiency virus- infected cells

Department of Immunology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Journal of Virology (Impact Factor: 4.65). 06/1999; 73(5):3893-903.
Source: PubMed

ABSTRACT Human monocytes and macrophages are persistent reservoirs of human immunodeficiency virus (HIV) type-1. Persistent HIV infection of these cells results in increased levels of NF-kappaB in the nucleus secondary to increased IkappaBalpha, IkappaBbeta, and IkappaBepsilon degradation, a mechanism postulated to regulate viral persistence. To characterize the molecular mechanisms regulating HIV-mediated degradation of IkappaB, we have sought to identify the regulatory domains of IkappaBalpha targeted by HIV infection. Using monocytic cells stably expressing different transdominant molecules of IkappaBalpha, we determined that persistent HIV infection of these cells targets the NH2 but not the COOH terminus of IkappaBalpha. Further analysis demonstrated that phosphorylation at S32 and S36 is necessary for HIV-dependent IkappaBalpha degradation and NF-kappaB activation. Of the putative N-terminal IkappaBalpha kinases, we demonstrated that the Ikappakappa complex, but not p90(rsk), is activated by HIV infection and mediates HIV-dependent NF-kappaB activation. Analysis of viral replication in cells that constitutively express IkappaBalpha negative transdominant molecules demonstrated a lack of correlation between virus-induced NF-kappaB (p65/p50) nuclear translocation and degree of viral persistence in human monocytes.

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    • "Nuclear and cytoplasmic extracts were prepared as described previously (Asin et al, 1999), with minor modications. Cells were washed with cold PBS twice, gently scraped from the dishes, transferred to microcentrifuge tubes, and centrifuged for 10 minutes at 3,000 £ g. "
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