Synchronized HIV assembly by tunable PIP<sub>2</sub> changes reveals PIP<sub>2</sub> requirement for stable Gag anchoring.

Mücksch, Frauke; Laketa, Vibor; Müller, Barbara; Schultz, Carsten; Kräusslich, Hans-Georg · Elife · 2017

basic_science · Level V

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Abstract

HIV-1 assembles at the plasma membrane (PM) of infected cells. PM association of the main structural protein Gag depends on its myristoylated MA domain and PM PI(4,5)P<sub>2</sub>. Using a novel chemical biology tool that allows rapidly tunable manipulation of PI(4,5)P<sub>2</sub> levels in living cells, we show that depletion of PI(4,5)P<sub>2</sub> completely prevents Gag PM targeting and assembly site formation. Unexpectedly, PI(4,5)P<sub>2</sub> depletion also caused loss of pre-assembled Gag lattices from the PM. Subsequent restoration of PM PI(4,5)P<sub>2</sub> reinduced assembly site formation even in the absence of new protein synthesis, indicating that the dissociated Gag molecules remained assembly competent. These results reveal an important role of PI(4,5)P<sub>2</sub> for HIV-1 morphogenesis beyond Gag recruitment to the PM and suggest a dynamic equilibrium of Gag-lipid interactions. Furthermore, they establish an experimental system that permits synchronized induction of HIV-1 assembly leading to induced production of infectious virions by targeted modulation of Gag PM targeting.

Medical subject headings