Mason-Pfizer Monkey Virus Envelope Glycoprotein Cycling and Its Vesicular Co-Transport with Immature Particles

Abstract

The envelope glycoprotein (Env) plays a crucial role in the retroviral life cycle by mediating primary interactions with the host cell. As described previously and expanded on in this paper, Env mediates the trafficking of immature Mason-Pfizer monkey virus (M-PMV) particles to the plasma membrane (PM). Using a panel of labeled RabGTPases as endosomal markers, we identified Env mostly in Rab7a- and Rab9a-positive endosomes. Based on an analysis of the transport of recombinant fluorescently labeled M-PMV Gag and Env proteins, we propose a putative mechanism of the intracellular trafficking of M-PMV Env and immature particles. According to this model, a portion of Env is targeted from the trans-Golgi network (TGN) to Rab7a-positive endosomes. It is then transported to Rab9a-positive endosomes and back to the TGN. It is at the Rab9a vesicles where the immature particles may anchor to the membranes of the Env-containing vesicles, preventing Env recycling to the TGN. These Gag-associated vesicles are then transported to the plasma membrane.

The Current View of Retroviruses as Seen from the Shoulders of a Giant

“…BCA3, which is incorporated into HIV-1 particles by its ability to interact with PKAc may be one of such factors, as shown in Rumlová et al [31]. The paper by Grznárová-Prokšová et al [32] contributes to our understanding of targeting the preassembled D-type immature particles to the plasma membrane and acquisition of the Env glycoproteins during this vesicle-mediated process. The restriction factors are represented by SAMHD1 and its role in the down-regulation of HIV dynamics in macrophages [33].…”