Flexible use of nuclear import pathways by HIV-1

Strategies to inhibit viral protein nuclear import: HIV-1 as a target

Nuclear import is a critical step in the life cycle of HIV-1. During the early (preintegration) stages of infection, HIV-1 has to transport its preintegration complex into the nucleus for integration into the host cell chromatin, while at the later (postintegration) stages viral regulatory proteins Tat and Rev need to get into the nucleus to stimulate transcription and regulate splicing and nuclear export of subgenomic and genomic RNAs. Given such important role of nuclear import in HIV-1 life cycle, this step presents an attractive target for antiviral therapeutic intervention. In this review, we describe the current state of our understanding of the interactions regulating nuclear import of the HIV-1 preintegration complex and describe current approaches to inhibit it. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.

HIV Nuclear Entry: Clearing the Fog

HIV-1 and other lentiviruses have the unusual capability of infecting nondividing cells, but the mechanism by which they cross an intact nuclear membrane is mysterious. Recent work, including a new study (Lee, K.; Ambrose, Z.; Martin, T.D.; Oztop, I.; Mulky, A.; Julias, J.G.; Vandergraaff, N.; Baumann, J.G.; Wang, R.; Yuen, W. et al. Flexible use of nuclear import pathways by HIV-1. Cell Host Microbe2010, 7, 221–233) confirms that the viral capsid plays a key role in HIV-1 nuclear entry in both dividing and nondividing cells. The identification of mutations in the viral capsid that alter the virus’s dependence on host cell nucleoporins represents an important advance in this poorly understood stage of the virus life cycle.