Imaging of HIV/host protein interactions

Abstract

HIV-1 relies on a myriad of interactions with host cell proteins to carry out its life cycle. Traditional biochemical approaches to probe protein-protein interactions are limited in their ability to study the spatial and dynamic interactions that take place in the context of an intact cell. However, issues such as localization and dynamics of interactions between viral and host proteins can be well addressed utilizing fluorescent imaging methods. The past decade has brought about the development of many novel fluorescent imaging techniques which have proved useful to describe the interaction of HIV-1 proteins with the host cell.

Fig. 1

Fluorescence resonance energy transfer (FRET). (a) No interaction. CFP and YFP are attached to the proteins of interest. Proteins do not interact, so no energy is transferred to YFP. (b) Interacting proteins. Proteins interact, and the energy emitted by CFP is transferred to and excites YFP

Fig. 2

Bifluorescence complementation (BiFc). (a) No interaction. GFP is split into two halves which cannot fluoresce alone and attached to the proteins of interest. Proteins do not interact, so no fluorescent signal is produced. (b) Interacting proteins. Proteins interact, allowing the two halves of GFP to come together and produce a fluorescent signal

Fig. 3

Total internal reflection fluorescence (TIRF) microscopy. Approaching light at the critical angle undergoes total internal reflection back through the glass coverslip An evanescent wave is created on the other side of the glass, extending approximately 100 nm into the sample. As only this extremely thin region is illuminated, background fluorescence from out-of-focus light is dramatically decreased, creating greater sensitivity

Fig. 4

HIV-1 Life Cycle

Fig. 5

GFP-Vpr can be used to visualize HIV-1 trafficking within living cells