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Hydrophobic domains of mouse polyomavirus minor capsid proteins promote membrane association and virus exit from the ER
Author(s) -
Huérfano Sandra,
Ryabchenko Boris,
Španielová Hana,
Forstová Jitka
Publication year - 2017
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14033
Subject(s) - capsid , endoplasmic reticulum , mutant , biology , virus , membrane protein , viral protein , mutation , membrane , microbiology and biotechnology , biochemistry , virology , gene
The minor structural protein VP 2 and its shorter variant, VP 3, of mouse polyomavirus ( MP yV) are essential for virus exit from the endoplasmic reticulum ( ER ) during viral trafficking to the nucleus. Here, we followed the role of putative hydrophobic domains ( HD ) of the minor proteins in membrane affinity and viral infectivity. We prepared variants of VP 2, each mutated to decrease hydrophobicity of one of three predicted hydrophobic domains: VP 2‐ mHD 1, VP 2‐ mHD 2 or VP 2‐ mHD 3 mutated in HD 1 (amino acids (aa) 60–101), HD 2 (aa 125–165) or HD 3 (aa 287–307), respectively. Transient production of the mutated proteins revealed that only VP 2‐ mHD 2 lost the affinity for intracellular membranes. Cytotoxicity connected with the ability of VP 2/ VP 3 to perforate membranes decreased markedly for VP 2‐ mHD 2, but only slightly for VP 2‐ mHD 1. The mutant VP 2‐ mHD 3 exhibited properties similar to the wild‐type protein. MP yV genomes, each carrying one of the mutations, were prepared for virus production. MP yV‐ mHD 1 and MP yV‐ mHD 2 viruses could be isolated, while the HD 3 mutation in VP 2/ VP 3 prevented virus assembly. We found that both MP yV‐ mHD 1 and MP yV‐ mHD 2 viruses arrived at the ER without delay and were processed by ER residential enzymes. However, the ability to associate with ER membranes was decreased in the case of MP yV‐ mHD 1 and practically abolished in the case of MP yV‐ mHD 2. Interestingly, while MP yV‐ mHD 2 was not infectious, infection of MP yV‐ mHD 1 virus was delayed. These findings reveal that HD 2, common to both VP 2 and VP 3, is responsible for the membrane binding properties of the minor proteins, while HD 1 of VP 2 is likely required to stabilize VP 2–membrane association and to enhance viral exit from the ER.