Arf1:Nef:endosomal CD4 myristoylated Nef Protein (numerous variants) Formation of a Nef:ARF1:CD4 complex Authored: Gillespie, ME, 2007-07-25 19:42:36 Pubmed15202998 Reactome Database ID Release 43200879 Reactome, http://www.reactome.org ReactomeREACT_11227 Reviewed: Skowronski, J, 2007-08-07 14:33:41 The HIV Nef protein downregulates CD4 through sequential connection with clathrin-coated pits and the COP1 coatomer, resulting in accelerated endocytosis and lysosomal targeting. The small GTPase ARF1 controls the Nef-induced, COP-mediated late-endosomal targeting of CD4. Nef binds ARF1 directly and can recruit the GTPase onto endosomal membranes, leading to the eventual degradation of CD4 (Faure et al. 2004).