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Structural basis of membrane budding by the nuclear egress complex of herpesviruses
Author(s) -
Bigalke Janna M,
Heldwein Ekaterina E
Publication year - 2015
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.15252/embj.201592359
Subject(s) - budding , biology , nuclear pore , microbiology and biotechnology , cytoplasm , inner membrane , biophysics , capsid , nuclear membrane , virology , virus , mitochondrion
During nuclear egress, herpesvirus capsids bud at the inner nuclear membrane forming perinuclear viral particles that subsequently fuse with the outer nuclear membrane, releasing capsids into the cytoplasm. This unusual budding process is mediated by the nuclear egress complex ( NEC ) composed of two conserved viral proteins, UL 31 and UL 34. Earlier, we discovered that the herpesvirus nuclear egress complex ( NEC ) could bud synthetic membranes in vitro without the help of other proteins by forming a coat‐like hexagonal scaffold inside the budding membrane. To understand the structural basis of NEC ‐mediated membrane budding, we determined the crystal structures of the NEC from two herpesviruses. The hexagonal lattice observed in the NEC crystals recapitulates the honeycomb coats within the budded vesicles. Perturbation of the oligomeric interfaces through mutagenesis blocks budding in vitro confirming that NEC oligomerization into a honeycomb lattice drives budding. The structure represents the first atomic‐level view of an oligomeric array formed by a membrane‐deforming protein, making possible the dissection of its unique budding mechanism and the design of inhibitors to block it.