Direct Formation of Vaccinia Virus Membranes from the Endoplasmic Reticulum in the Absence of the Newly Characterized L2-Interacting Protein A30.5

Maruri-Avidal, Liliana; Weisberg, Andrea S.; Moss, Bernard

doi:10.1128/jvi.02137-13

Cited by 43 publications

(57 citation statements)

References 50 publications

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“…There are at least 5 proteins in this group, varying in size from 5 to 20 kDa for A30.5, L2, and H7 and around 40 kDa for A11 and A6. A6 and H7 are localized predominantly in the cytosol (18,32,39), while L2 and A30.5 are localized in the ER (19,21), and A11 associates with viral membranes (40,41). How these diverse proteins function together to facilitate acquisition of membranes from the ER is an intriguing question.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, we determined the crystal structure of VACV H7, which is one of the poxvirus viral membrane assembly proteins (VMAPs) (21). VMAPs are proteins that were recently discovered, through viral genetics, to be essential for poxvirus membrane biogenesis.…”

Section: Discussionmentioning

confidence: 99%

“…The origin and biogenesis of the crescent membranes are among the least understood aspects of poxvirus biology, but several viral proteins that are involved in crescent formation were recently identified in vaccinia virus (VACV), the prototypical poxvirus. These proteins, including A11 (17), H7 (18), L2 (19), A6 (20), and A30.5 (21), are collectively referred to as the viral membrane assembly proteins (VMAPs) (21). VMAPs were thought to work together to generate breaks in the ER membrane, to stabilize the open-ended crescent membranes, and to elongate the crescents by membrane fusion (21).…”

mentioning

confidence: 99%

“…These proteins, including A11 (17), H7 (18), L2 (19), A6 (20), and A30.5 (21), are collectively referred to as the viral membrane assembly proteins (VMAPs) (21). VMAPs were thought to work together to generate breaks in the ER membrane, to stabilize the open-ended crescent membranes, and to elongate the crescents by membrane fusion (21). However, the functions of the individual VMAPs and how VMAPs work together are unknown.…”

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confidence: 99%

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Structure-Function Analysis of Vaccinia Virus H7 Protein Reveals a Novel Phosphoinositide Binding Fold Essential for Poxvirus Replication

Kolli

Meng

et al. 2015

J Virol

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Phosphoinositides and phosphoinositide binding proteins play a critical role in membrane and protein trafficking in eukaryotes. Their critical role in replication of cytoplasmic viruses has just begun to be understood. Poxviruses, a family of large cytoplasmic DNA viruses, rely on the intracellular membranes to develop their envelope, and poxvirus morphogenesis requires enzymes from the cellular phosphoinositide metabolic pathway. However, the role of phosphoinositides in poxvirus replication remains unclear, and no poxvirus proteins show any homology to eukaryotic phosphoinositide binding domains. Recently, a group of poxvirus proteins, termed viral membrane assembly proteins (VMAPs), were identified as essential for poxvirus membrane biogenesis. A key component of VMAPs is the H7 protein. Here we report the crystal structure of the H7 protein from vaccinia virus. The H7 structure displays a novel fold comprised of seven ␣-helices and a highly curved three-stranded antiparallel ␤-sheet. We identified a phosphoinositide binding site in H7, comprised of basic residues on a surface patch and the flexible C-terminal tail. These residues were found to be essential for viral replication and for binding of H7 to phosphatidylinositol-3-phosphate (PI3P) and phosphatidylinositol-4-phosphate (PI4P). Our studies suggest that phosphoinositide binding by H7 plays an essential role in poxvirus membrane biogenesis. IMPORTANCEPoxvirus viral membrane assembly proteins (VMAPs) were recently shown to be essential for poxvirus membrane biogenesis. One of the key components of VMAPs is the H7 protein. However, no known structural motifs could be identified from its sequence, and there are no homologs of H7 outside the poxvirus family to suggest a biochemical function. We have determined the crystal structure of the vaccinia virus (VACV) H7 protein. The structure displays a novel fold with a distinct and positively charged surface. Our data demonstrate that H7 binds phosphatidylinositol-3-phosphate and phosphatidylinositol-4-phosphate and that the basic surface patch is indeed required for phosphoinositide binding. In addition, mutation of positively charged residues required for lipid binding disrupted VACV replication. Phosphoinositides and phosphoinositide binding proteins play critical roles in membrane and protein trafficking in eukaryotes. Our study demonstrates that VACV H7 displays a novel fold for phosphoinositide binding, which is essential for poxvirus replication. P hosphoinositides are lipids derived from reversible phosphorylation of phosphatidylinositol at positions 3, 4, and 5 of the inositol head group (1). They include three monophosphorylated (phosphatidylinositol-3-phosphate [PI3P], PI4P, and PI5P), three bisphosphorylated [PI(3,4)P 2 , PI(3,5)P 2 , and PI(4,5)P 2 ], and one trisphosphorylated [PI(3,4,5)P 3 ] isoform. Cellular organelles are partially defined by their phosphoinositide compositions, and specific recognition of phosphoinositides on different organelles is crucial for protein sorting and memb...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Structure-Function Analysis of Vaccinia Virus H7 Protein Reveals a Novel Phosphoinositide Binding Fold Essential for Poxvirus Replication

Kolli

Meng

et al. 2015

J Virol

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“…Complementing cell lines have also been used to make deletion mutants, particularly for early genes (82)(83)(84). With general methods for making conditional mutants and available technologies, we turned our attention to interrogating the steps in the poxvirus replication cycle including entry (85,86), regulation of gene expression (87), genome replication (88), cytoplasmic disulfide bond formation (89), and virion assembly (90,91). Although much work remains to be done, at least some role has been assigned to all 100 essential genes (92).…”

Section: From Biochemistry To Virologymentioning

confidence: 99%