Abstract
Immune stimulation fuels cell signaling-transcriptional programs inducing biological responses to eliminate virus-infected cells. Yet, retroviruses that integrate into host cell chromatin, such as HIV-1, co-opt these programs to switch between latent and reactivated states; however, the regulatory mechanisms are still unfolding. Here, we implemented a functional screen leveraging HIV-1’s dependence on CD4+ T cell signaling-transcriptional programs and discovered ADAP1 is an undescribed modulator of HIV-1 proviral fate. Specifically, we report ADAP1 (ArfGAP with dual PH domain-containing protein 1), a previously thought neuronal-restricted factor, is an amplifier of select T cell signaling programs. Using complementary biochemical and cellular assays, we demonstrate ADAP1 inducibly interacts with the immune signalosome to directly stimulate KRAS GTPase activity thereby augmenting T cell signaling through targeted activation of the ERK–AP-1 axis. Single cell transcriptomics analysis revealed loss of ADAP1 function blunts gene programs upon T cell stimulation consequently dampening latent HIV-1 reactivation. Our combined experimental approach defines ADAP1 as an unexpected tuner of T cell programs facilitating HIV-1 latency escape.
Highlights
Immune stimulation fuels cell signaling-transcriptional programs inducing biological responses to eliminate virus-infected cells
69 positive pools were identified in the two parallel screens (FDR < 2.5%, multiple unpaired t-test) (Fig. 1d and Supplementary Fig. 1c) as potentially containing a cDNA encoding a latent HIV-1 activating factor
By ectopically expressing previously described GTPase activating protein (GAP) (C24A, GAP Mut) and membrane-binding (R149C, PH1 Mut) deficient mutants[22] in Jkt-HIVLuc cells, which are ADAP1 deficient (Fig. 1g), we found both mutants had statistically significant decreases in luciferase activity when compared to wild-type (WT) ADAP1 (~1.7-fold, and ~1.4-fold respectively, p < 0.01, paired t-test) (Fig. 1h), signifying ADAP1 requires both GAP domain and plasma membrane-binding to promote latent HIV-1 reactivation
Summary
Immune stimulation fuels cell signaling-transcriptional programs inducing biological responses to eliminate virus-infected cells. Barring eradication efforts, infection can be re-established upon therapy cessation due to the expansion of T cells harboring latent yet replicationcompetent proviruses[6], motivating the need for understanding effector programs licensing HIV-1 persistence. It remains poorly understood which inducible host cell factors regulate these effector programs. Loss of ADAP1 function coupled with single cell transcriptomic analysis support a model whereby ADAP1 tunes T cell gene programs influencing HIV-1 transcriptional activation potential, implicating ADAP1 as an undescribed T cell signaling-transcriptional tuner that modulates HIV-1 proviral fate
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