[TIP47: a cellular factor required for envelope glycoproteins incorporation into HIV particles]

The production of Human Immunodeficiency Virus-1 (HIV-1), the causative agent of AIDS, requires many interactions between viral and host cell proteins at each step of the viral cycle. The late steps of the replicative cycle of HIV-1 permit the formation of new infectious virions. These steps consist of assembly and budding of the particle, as well as the envelope glycoproteins incorporation step. Several research teams have tried to elucidate the molecular mechanism controlling the envelope glycoproteins (Env) incorporation. Recently, the first cellular cofactor required for this step, Tail-Interacting Protein of 47 kDa (TIP47), has been identified. TIP47 is required for the generation of an infectious viral particle and for the incorporation of the envelope glycoproteins into virions. In this review, we emphasize the key roles of the two major viral structural proteins, Gag and Env, in the last steps of the replicative cycle of HIV-1. We describe the biology of TIP47 and its role as a bridge between Gag and Env, during Env incorporation into new viral particles. Studies discussed in the review illustrate the key roles of proteins implicated in the intracellular trafficking pathways during the formation of the virus.