Exosomes and HIV Gag bud from endosome-like domains of the T cell plasma membrane

Authors:
Booth AM, Fang Y, Fallon JK, Yang JM, Hildreth JE, Gould SJ
In:
Source: J Cell Biol
Publication Date: (2006)
Issue: 172(6): 923-35
Research Area:
Immunotherapy / Hematology
Cells used in publication:
K-562
Species: human
Tissue Origin: blood
Jurkat
Species: human
Tissue Origin: blood
Jurkat-modified
Species: human
Tissue Origin:
Platform:
Nucleofectorâ„¢ I/II/2b
Abstract
Exosomes are secreted, single membrane organelles of approximately 100 nm diameter. Their biogenesis is typically thought to occur in a two-step process involving (1) outward vesicle budding at limiting membranes of endosomes (outward = away from the cytoplasm), which generates intralumenal vesicles, followed by (2) endosome-plasma membrane fusion, which releases these internal vesicles into the extracellular milieu as exosomes. In this study, we present evidence that certain cells, including Jurkat T cells, possess discrete domains of plasma membrane that are enriched for exosomal and endosomal proteins, retain the endosomal property of outward vesicle budding, and serve as sites of immediate exosome biogenesis. It has been hypothesized that retroviruses utilize the exosome biogenesis pathway for the formation of infectious particles. In support of this, we find that Jurkat T cells direct the key budding factor of HIV, HIV Gag, to these endosome-like domains of plasma membrane and secrete HIV Gag from the cell in exosomes.