Rabies virus utilizes neuropilin 2 as an endocytic receptor to trigger TGFBR1-mediated actin polymerization.

Abstract

Rabies virus (RABV), belonging to the rhabdovirus, is a typical large virus that enters cells via clathrin-mediated endocytosis (CME). RABV-containing pits are only partially clathrin-coated and require local actin polymerization for efficient internalization. This unconventional entry process suggests that a specific receptor may be required to initiate actin polymerization during RABV entry. Here, we found that RABV uses the cell membrane protein neuropilin 2 (NRP2) to initiate F-actin polymerization. NRP2 is required for RABV infection and directly interacts with RABV glycoprotein. An antibody against the ectodomain of NRP2 and the soluble ectodomain of NRP2 blocked RABV infection in cells. Expression of human NRP2 in non-susceptible DU145 cells enabled RABV infection. We further found that NRP2 interacted with transforming growth factor-β receptor I (TGFBR1), triggering TGFBR1/2-Cdc42-mediated F-actin polymerization. Vesicular stomatitis virus, another prototypical rhabdovirus, also uses a similar mechanism to enter cells. Our findings demonstrate that NRP2 is a novel receptor for RABV entry by transducing the signal of viral binding across the plasma membrane to initiate actin polymerization. NRP2 may represent one of the long-sought molecules that facilitate large pathogen cell entry via CME.IMPORTANCERabies virus (RABV) enters cells via clathrin-mediated endocytosis (CME), but RABV-containing pits are only partially clathrin-coated, requiring actin polymerization for efficient entry. However, how the virus triggers the actin polymerization remains unclear. Here, we found that the cell membrane protein neuropilin 2 (NRP2) is required for RABV infection and directly interacts with RABV glycoprotein. An antibody against the ectodomain of NRP2 and the soluble ectodomain of NRP2 blocked RABV infection in cells. Expression of human NRP2 in non-susceptible DU145 cells enabled RABV infection. We further found that NRP2 interacted with transforming growth factor-β receptor I (TGFBR1), triggering TGFBR1/2-Cdc42-mediated F-actin polymerization. Vesicular stomatitis virus, another prototypical rhabdovirus, also uses a similar mechanism to enter cells. Our findings demonstrate that NRP2 is a novel receptor for RABV entry by initiating actin polymerization and may represent one of the long-sought molecules that facilitate large pathogen cell entry via CME.