Two distinct modes of ESCRT-III recognition are required for VPS4 functions in lysosomal protein targeting and HIV-1 budding.
The ESCRT pathway mediates membrane remodeling during enveloped virus budding, cytokinesis, and intralumenal endosomal vesicle formation. Late in the pathway, a subset of membrane-associated ESCRT-III proteins display terminal amphipathic "MIM1" helices that bind and recruit VPS4 ATPases via their MIT domains. We now report that VPS4 MIT domains also bind a second, "MIM2" motif found in a different subset of ESCRT-III subunits. The solution structure of the VPS4 MIT-CHMP6 MIM2 complex revealed that MIM2 elements bind in extended conformations along the groove between the first and third helices of the MIT domain. Mutations that block VPS4 MIT-MIM2 interactions inhibit VPS4 recruitment, lysosomal protein targeting, and HIV-1 budding. MIT-MIM2 interactions appear to be common throughout the ESCRT pathway and possibly elsewhere, and we suggest how these interactions could contribute to a mechanism in which VPS4 and ESCRT-III proteins function together to constrict the necks of budding vesicles.
Kieffer
Collin
C
Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA.
Skalicky
Jack J
JJ
Morita
Eiji
E
De Domenico
Ivana
I
Ward
Diane M
DM
Kaplan
Jerry
J
Sundquist
Wesley I
WI
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D015374:Biosensing Techniques; D017124:Conserved Sequence; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D011487:Protein Conformation; D025941:Protein Interaction Mapping; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017384:Sequence Deletion; D013059:Spectrum Analysis, Raman; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D011994:Recombinant Proteins; D033921:Vesicular Transport Proteins; D000251:Adenosine Triphosphatases