DC-SIGN initiates an immature dendritic cell phenotype triggering Rho activation that is utilised by HIV-1

DC-SIGN is a C-type lectin expressed by dendritic cells (DCs) that binds HIV-1, sequestering it within multivesicular bodies to facilitate transmission to CD4+ T cells. Here we characterize the molecular basis of signalling through DC-SIGN by large-scale gene expression profiling and phosphoproteome analysis. Solitary DC-SIGN activation leads to a phenotypically disparate transcriptional program from Toll-like receptor (TLR) triggering with downregulation of MHC II, CD86, and interferon response genes and with induction of the TLR negative regulator ATF3. Phosphoproteome analysis reveals DC-SIGN signals through the leukemia-associated Rho guanine nucleotide exchange factor (LARG) to induce Rho activity. This LARG activation also occurs on DC HIV exposure and is required for effective HIV viral synapse formation. Taken together HIV mediated DC-SIGN signalling provides a mechanism by which HIV evades the immune response yet induces viral spread.

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Hodges A, Sharrocks K, Edelmann M, Baban D, Moris A, Schwartz O, Drakesmith H, Davies K, Kessler B, McMichael A, Simmons A