Structural basis for autoinhibition of ESCRT-III CHMP3.
Endosomal sorting complexes required for transport (ESCRT-0, ESCRT-I, ESCRT-II, and ESCRT-III) are selectively recruited to cellular membranes to exert their function in diverse processes, such as multivesicular body biogenesis, enveloped virus budding, and cytokinesis. ESCRT-III is composed of members of the charged multivesicular body protein (CHMP) family--cytosolic proteins that are targeted to membranes via yet unknown signals. Membrane targeting is thought to result in a membrane-associated protein network that presumably acts at a late budding step. Here we provide structural evidence based on small-angle X-ray scattering data that ESCRT-III CHMP3 can adopt two conformations in solution: a closed globular form that most likely represents the cytosolic conformation and an open extended conformation that might represent the activated form of CHMP3. Both the closed and open conformations of CHMP3 interact with AMSH with high affinity. Although the C-terminal region of CHMP3 is required for AMSH interaction, a peptide thereof reveals only weak binding to AMSH, suggesting that other regions of CHMP3 contribute to the high-affinity interaction. Thus, AMSH, including its MIT (microtubule interacting and transport) domain, interacts with ESCRT-III CHMP3 differently from reported Vps4 MIT domain-CHMP protein interactions.
Lata
Suman
S
Unit for Virus Host Cell Interaction, UMR 5233 UJF-EMBL-CNRS, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France.
Roessle
Manfred
M
Solomons
Julianna
J
Jamin
Marc
M
Gottlinger
Heinrich G
HG
Svergun
Dmitri I
DI
Weissenhorn
Winfried
W
D002151:Calorimetry; D002942:Circular Dichroism; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D043222:Ubiquitin Thiolesterase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D009419:Nerve Tissue Proteins; D043222:Ubiquitin Thiolesterase