Based on the observation that DENV induces significant rearrangements in the membrane architecture of infected cells, together with its distinct susceptibility to inhibitors of FAS, it was our hypothesis that lipid biosynthesis was important to DENV replication. Therefore, to investigate whether the intracellular lipid composition was altered during DENV infection, we carried out LC-MS-based analyses of the global lipidome of mosquito cells infected with DENV. To differentiate between changes to the lipid profile that occurred upon exposure to infectious virus versus that induced by virus entry alone, we included UV-inactivated DENV (UV-DENV) in the studies. This inactivated virus is only capable of binding, entry and initial rounds of viral RNA translation but does not have the ability to replicate its genome. Figure 2 shows a principle component analysis (PCA) plot of the overall lipid abundance in C6/36 mosquito cells infected with either DENV or UV-DENV at 36 and 60 hr post-infection. The 36 hr time point was chosen to represent a peak in viral replication while the 60 hr time point represents late stages of replication as well as increased cellular stress. Our previous analysis of earlier time points (ie. 24 hr post-infection) indicated that concurrent with increasing RNA synthesis activity and virus release, there were substantial changes in the lipidome of infected cells. Some of these changes were greater (higher fold changes) than those observed at the 36 hr time point. However, the overall intensities of the expressed lipids was lower contributing to a low signal to noise ratio. Furthermore, the number of species expressed at significant levels (p,0.05) were limited. Therefore, we chose to pursue the later time points. Under conditions that ensured that all cells were infected (multiplicity of infection of 20), optimal viral RNA synthesis occurred between 24-36 hr post infection (data not shown). A total of 7217 features observed in the LC-MS analyses were included in the PCA analyses. The plot shows specific segregation of lipid profiles between DENV and UV-DENV exposed cells compared to uninfected cells (mock). A temporal regulation of the lipid profile was also observed. However, this is more discernible upon analysis of individual lipid species (Figure 3 ) rather than in the PCA analysis. Overall, in this whole cell analysis