title: Cytomegalovirus pUL50 is the multi-interacting determinant of the core nuclear egress complex (NEC) that recruits cellular accessory NEC components.
abstract: Nuclear egress of herpesvirus capsids through the nuclear envelope is mediated by the multimeric nuclear egress complex (NEC). The human cytomegalovirus (HCMV) core NEC is defined by an interaction between the membrane-anchored pUL50 and its nuclear co-factor pUL53, tightly associated through heterodimeric corecruitment to the nuclear envelope. Cellular proteins, such as p32/gC1qR, emerin and protein kinase C (PKC), are recruited by direct interaction with pUL50 for the multimeric extension of the NEC. As a functionally important event, the recruitment of both viral and cellular protein kinases leads to site-specific lamin phosphorylation and nuclear lamina disassembly. In this study, interaction domains within pUL50 for its binding partners were defined by co-immunoprecipitation. The interaction domain for pUL53 is located within the pUL50 N-terminus (residues 10-169), interaction domains for p32/gC1qR (100-358) and PKC (100-280) overlap in the central part of pUL50, and the interaction domain for emerin is located in the C-terminus (265-397). Moreover, expression and formation of core NEC proteins at the nuclear rim were consistently detected in cells permissive for productive HCMV replication, including two trophoblast-cell lines. Importantly, regular nuclear-rim formation of the core NEC was blocked by inhibition of cyclin-dependent kinase (CDK) activity. In relation to the recently published crystal structure of the HCMV core NEC, our findings result in a refined view of NEC assembly. In particular, we suggest that CDKs may play an important regulatory role in NEC formation during HCMV replication.
authors.affiliation: Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Sonntag
authors.affiliation: Virology Division, SEALS Microbiology, Prince of Wales Hospital, Sydney, Australia.
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Hamilton
authors.affiliation: Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: Hanife
authors.initials: H
authors.lastname: Bahsi
authors.affiliation: Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Wagner
authors.affiliation: Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.
authors.forename: Stipan
authors.initials: S
authors.lastname: Jonjic
authors.affiliation: Virology Division, SEALS Microbiology, Prince of Wales Hospital, Sydney, Australia.
authors.forename: William D
authors.initials: WD
authors.lastname: Rawlinson
authors.affiliation: Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Marschall
authors.affiliation: Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Milbradt
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D003587:Cytomegalovirus / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D009685:Nuclear Envelope / Q000821:virology*; D034881:Nuclear Lamina / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D060066:Protein Interaction Maps; D051571:Protein Kinase C-alpha / Q000378:metabolism; D017434:Protein Structure, Tertiary; D014764:Viral Proteins / Q000378:metabolism*; D057074:Virus Release / Q000502:physiology*; D014779:Virus Replication / Q000502:physiology*
chemical_list: C087299:C1QBP protein, human; D002352:Carrier Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D014764:Viral Proteins; C092710:emerin; C523758:pUL50 protein, cytomegalovirus; C523759:pUL53 protein, cytomegalovirus; C496628:PRKCA protein, human; D051571:Protein Kinase C-alpha; D018844:Cyclin-Dependent Kinases