RT Journal Article
SR Electronic
T1 Mechanism of Vps4 hexamer function revealed by cryo-EM
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP e1700325
DO 10.1126/sciadv.1700325
VO 3
IS 4
A1 Su, Min
A1 Guo, Emily Z.
A1 Ding, Xinqiang
A1 Li, Yan
A1 Tarrasch, Jeffrey T.
A1 Brooks, Charles L.
A1 Xu, Zhaohui
A1 Skiniotis, Georgios
YR 2017
UL http://advances.sciencemag.org/content/3/4/e1700325.abstract
AB Vps4 is a member of AAA+ ATPase (adenosine triphosphatase associated with diverse cellular activities) that operates as an oligomer to disassemble ESCRT-III (endosomal sorting complex required for transport III) filaments, thereby catalyzing the final step in multiple ESCRT-dependent membrane remodeling events. We used electron cryo-microscopy to visualize oligomers of a hydrolysis-deficient Vps4 (vacuolar protein sorting-associated protein 4) mutant in the presence of adenosine 5′-triphosphate (ATP). We show that Vps4 subunits assemble into an asymmetric hexameric ring following an approximate helical path that sequentially stacks substrate-binding loops along the central pore. The hexamer is observed to adopt an open or closed ring configuration facilitated by major conformational changes in a single subunit. The structural transition of the mobile Vps4 subunit results in the repositioning of its substrate-binding loop from the top to the bottom of the central pore, with an associated translation of 33 Å. These structures, along with mutant-doping experiments and functional assays, provide evidence for a sequential and processive ATP hydrolysis mechanism by which Vps4 hexamers disassemble ESCRT-III filaments.