HIV-1 Nef Induces a Rab11-Dependent Routing of Endocytosed Immune Costimulatory Proteins CD80 and CD86 to the Golgi

Abstract

The Nef protein of HIV-1 removes the immune costimulatory proteins CD80 and CD86 from the cell surface by a unique clathrin- and dynamin-independent, actin-based endocytic pathway that deploys coupled activation of c-src and Rac. In this study, we show that, similar to major histocompatibility complex class I (MHCI), Nef subsequently reroutes CD80 and CD86 to the Golgi region. However, not only are CD80/CD86 internalized by a different mechanism from MHCI but also the vesicular pathway of Golgi delivery for CD80/CD86 is distinct from that employed for MHCI. While MHCI passes through early endosomal and sorting compartments marked by Rab5/early embryonic antigen 1 and ADP ribosylation factor 6, respectively, CD80 and CD86 enter endocytic vesicles that do not acquire conventional early endosomal markers but remain accessible to fluid probes. Rather than being delivered to preexisting Rab11-positive recycling compartments, these vesicles recruit Rab11 de novo. Rab11 activity is also necessary for the delivery of CD80/CD86 in these transitional vesicles to the Golgi region. These data reveal an unusual pathway of endocytic vesicular traffic to the Golgi and its recruitment in a viral immune evasion strategy.