Budding

Definition

Budding is the process of lipid envelopment of viral particles by the cell membrane during exit from infected cells, a strategy that allows the virus to bypass the need for cell lysis to release newly formed virions and spread infection. As HIV-1 assembly progresses at the plasma membrane, viral capsids form on the inner leaflet of the cell surface and become gradually surrounded by the plasma membrane. In late steps of budding, the fully assembled immature capsids are completely surrounded by the membrane but remain connected to the cell by a membranous stalk. The ultimate separation of nascent virions from their progenitor cells involves host proteins of the endosomal sorting complex required for transport (ESCRT) pathway, a cell membrane fission machinery that will place the final cut and release the newly made virions.

Introduction

HIV-1 budding requires nascent virions to traverse the plasma membrane and acquire their envelope, a process that begins with the enfoldment...