The TIM and TAM Families of Phosphatidylserine Receptors Mediate Dengue Virus Entry

SummaryDengue viruses (DVs) are responsible for the most medically relevant arboviral diseases. However, the molecular interactions mediating DV entry are poorly understood. We determined that TIM and TAM proteins, two receptor families that mediate the phosphatidylserine (PtdSer)-dependent phagocytic removal of apoptotic cells, serve as DV entry factors. Cells poorly susceptible to DV are robustly infected after ectopic expression of TIM or TAM receptors. Conversely, DV infection of susceptible cells is inhibited by anti-TIM or anti-TAM antibodies or knockdown of TIM and TAM expression. TIM receptors facilitate DV entry by directly interacting with virion-associated PtdSer. TAM-mediated infection relies on indirect DV recognition, in which the TAM ligand Gas6 acts as a bridging molecule by binding to PtdSer within the virion. This dual mode of virus recognition by TIM and TAM receptors reveals how DVs usurp the apoptotic cell clearance pathway for infectious entry.

► A cDNA screen identifies TIM and TAM receptors as dengue virus entry factors
► Blocking TAM and TIM expression inhibits dengue virus infection of permissive cells
► TIM and TAM bind to virion-associated phosphatidylserine
► TAM receptor kinase activity is important for potentiation of viral infection