Regulation of HIV-1 nuclear transport by T cell activation

• Applicant: Professor Oliver T. Fackler, Ph.D.
• Subject Area: Virology ; Immunology ; Cell Biology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 568772942

HIV has to adapt its replication strategies to the specific cellular milieu in distinct target cell types but the limited accessibility of physiologically relevant targets to experimental manipulation presented a major barrier towards dissecting the molecular mechanism of this adaptation. We recently established an activation-neutral gene editing approach coupled to a comprehensive toolbox for the visualization and quantification of HIV-1 replication intermediates. These advances allow us for the first time to address the detailed molecular mechanisms of HIV-1 replication in truly resting primary CD4 T lymphocytes and compare them to genetically identically activated cells from the same donor. Our preliminary results defined that nucleoporin 62 (NUP62) exerts functions in resting CD4 T cells that oppose its established role in other cell types and regulates quantity as well as quality of HIV-1 capsid import in a T cell activation dependent manner: While in activated CD4 T cells, the depletion of NUP62 potently reduces nuclear import of HIV-1 capsids as well as the de novo synthesis of viral proteins, NUP62 depletion in resting CD4 T cell promotes nuclear import and viral protein synthesis. This proposal aims at dissecting the different molecular mechanisms of NUP62 action in these different cellular environments and define the functional relevance of the T cell activation-mediated functional switch for virus replication and innate immune recognition. Since our preliminary results identifies a selected group of cellular proteins as candidate cargo for this NUP62 dependent pathway, investigating the relevance of the novel NUP62-T cell activation module for cellular cargo and T cell function constitutes another important goal of this proposal. Stratified in four synergistic work packages we will (i) precisely map the steps at which NUP62 differentially regulates HIV-1 infection in CD4 T cells, (ii) dissect the general effects of NUP62 depletion on nuclear transport in CD4 T cell of different activation states, (iii) unravel the mechanism by which T cell activation regulates these processes and (iv) decipher the common principles by which cellular cargo is affected by this novel pathway and their functional role for HIV-1 infection and T cell activation. These efforts will provide important new insight in the replication strategies of HIV-1 in physiologically relevant target cells but also in fundamental principles of CD4 T cell biology.

• DFG Programme: Research Grants
• Co-Investigators: Marina Lusic, Ph.D.; Professorin Dr. Venera Weinhardt