Related Experiment Video
Updated: Aug 10, 2026

Imaging of HIV-1 Envelope-induced Virological Synapse and Signaling on Synthetic Lipid Bilayers
Published on: March 8, 2012
The HIV-1 Nef protein acts as a connector with sorting pathways in the Golgi and at the plasma membrane
A Mangasarian1, M Foti, C Aiken
1Infectious Disease Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Abstract:
The HIV Nef protein down-regulates the cell surface expression of CD4 and of MHC I at least in part through accelerated endocytosis. To investigate further the mechanism of this effect, we created chimeric integral membrane proteins comprising the extracellular and transmembrane regions of CD4 or CD8 and Nef as the cytoplasmic domain. These fusion molecules could down-modulate CD4 in trans in a dileucine-dependent manner. Furthermore, in spite of lacking receptor-derived internalization signals, the Nef-containing chimeras underwent both Golgi retention and rapid endocytosis via clathrin-coated pits. Taken together, these data suggest that Nef down-regulates CD4 and probably MHC I by physically connecting these receptors with sorting pathways in the Golgi and at the plasma membrane.
Related Concept Videos
The Early Endosome: Endocytosis of Transferrin
Nuclear Protein Sorting
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Rab Proteins
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Golgi Matrix Proteins
One of the first identified Golgi matrix proteins was GM130, a rod-like protein located in the cis-Golgi. Subsequently, many Golgi...
Inhibitors of Virion Maturation and Assembly

