Hm. Craig et al., Interactions of HIV-1 Nef with the mu subunits of adaptor protein complexes 1, 2, and 3: Role of the dileucine-based sorting motif, VIROLOGY, 271(1), 2000, pp. 9-17
HIV-1 Nef interacts with cellular adaptor protein (AP) complexes and their
medium (mu) subunits. However, the role of the dileucine-based sorting moti
f within Nef in these interactions has been incompletely characterized. Her
e, yeast two-hybrid assays indicated that HIV-1 Nef interacted not only wit
h the mu subunits of AP-1 and AP-2, but also with that of AP-3. The interac
tions with mu 1 and mu 3 were markedly stronger than the interaction with m
u 2. Leucine residues of the sorting motif were required for the interactio
ns with mu 3 and mu 2 and contributed to the interaction with mu 1. Confoca
l immunofluorescence microscopy indicated that Nef, AP-I, and AP-3 (but not
AP-2) were concentrated in a juxtanuclear region near the cell center, pot
entially facilitating interaction between Nei and the mu 1 and mu 3 subunit
s. However, leucine residues of the sorting motif were not required for thi
s subcellular localization of Nef. These data suggest that the dileucine mo
tif, required for optimal viral replication, functions through interactions
with a variety of AP complexes, including AP-3, potentially by recruiting
adaptor complexes to subcellular locations specified by additional determin
ants in the Nef protein. (C) 2000 Academic Press.