The cell attachment proteins of type 1 and type 3 reovirus are differentially susceptible to trypsin and chymotrypsin

Yeung, Michael C.; Lim, Dongbin; Duncan, Roy; Shahrabadi, M Shamsi; Cashdollar, L W; Lee, P. W. K.

doi:10.1016/0042-6822(89)90352-8

Cited by 38 publications

(43 citation statements)

References 29 publications

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“…3B and 4). Trypsin treatment of this group of expressed 1 proteins resulted in the generation of stable cleavage products of approximately 25 kDa, which is characteristic of trypsintreated wt T3D 1 (8,14,15,24,30,52). Thus, the pattern of susceptibility of chimeric 1 proteins to cleavage by trypsin confirms the location of a protease-sensitive region in T3D 1, T(iv), and is consistent with native folding of these molecules.…”

Section: Figsupporting

confidence: 50%

“…MAb 9BG5 binds sequences in the T3D 1 head domain (4,14,29,42,52). Consistent with the epitope specificity of 9BG5, wt T3D 1 and chimeric and truncated 1 proteins containing the T3D head were bound efficiently and specifically by this MAb (Fig.…”

Section: Discussionmentioning

confidence: 52%

“…Our findings permit discrete topographical assignment of receptor-binding activities of type 3 1 protein to morphologic region T(iii) of the tail (this study) and the head domain (8,14,29,30,42,50,52) (Fig. 8).…”

Section: Discussionmentioning

confidence: 95%

“…Using a panel of expressed chimeric and truncated 1 proteins derived from strains T1L and T3D, we found that sequences predicted to form an eight-stranded ␤-sheet in the T3D 1 tail are sufficient to mediate binding of sialic acid by T3D 1; the head domain, which contains sequences that bind an unidentified receptor on L cells (8,14,29,30,42,50,52), is dispensable for sialic acid binding. Carbohydrate binding by type 1 1 protein also is mediated by sequences in the tail predicted to form a ␤-sheet structure; however, these sequences are contained in a morphologic region of the tail, T(iv), that is distinct from that involved in binding sialic acid by type 3 1.…”

Section: Discussionmentioning

confidence: 99%

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Identification of Carbohydrate-Binding Domains in the Attachment Proteins of Type 1 and Type 3 Reoviruses

Chappell

Duong

Wright

et al. 2000

J Virol

107

130

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The reovirus attachment protein, 1, is responsible for strain-specific patterns of viral tropism in the murine central nervous system and receptor binding on cultured cells. The 1 protein consists of a fibrous tail domain proximal to the virion surface and a virion-distal globular head domain. To better understand mechanisms of reovirus attachment to cells, we conducted studies to identify the region of 1 that binds cell surface carbohydrate. Chimeric and truncated 1 proteins derived from prototype reovirus strains type 1 Lang (T1L) and type 3 Dearing (T3D) were expressed in insect cells by using a baculovirus vector. Assessment of expressed protein susceptibility to proteolytic cleavage, binding to anti-1 antibodies, and oligomerization indicates that the chimeric and truncated 1 proteins are properly folded. To assess carbohydrate binding, recombinant 1 proteins were tested for the capacity to agglutinate mammalian erythrocytes and to bind sialic acid presented on glycophorin, the cell surface molecule bound by type 3 reovirus on human erythrocytes. Using a panel of two wild-type and ten chimeric and truncated 1 proteins, the sialic acid-binding domain of type 3 1 was mapped to a region of sequence proposed to form the more amino terminal of two predicted ␤-sheet structures in the tail. This unit corresponds to morphologic region T(iii) observed in computer-processed electron micrographs of 1 protein purified from virions. In contrast, the homologous region of T1L 1 sequence was not implicated in carbohydrate binding; rather, sequences in the distal portion of the tail known as the neck were required.Results of these studies demonstrate that a functional receptor-binding domain, which uses sialic acid as its ligand, is contained within morphologic region T(iii) of the type 3 1 tail. Furthermore, our findings indicate that T1L and T3D 1 proteins contain different arrangements of receptor-binding domains.

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Section: Figsupporting

confidence: 50%

Section: Discussionmentioning

confidence: 52%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Identification of Carbohydrate-Binding Domains in the Attachment Proteins of Type 1 and Type 3 Reoviruses

Chappell

Duong

Wright

et al. 2000

J Virol

107

130

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“…The 1 trimer is highly asymmetric, with an N-terminal fibrous tail that is anchored to the virion and a C-terminal globular head that interacts with the cell receptor (23)(24)(25)(26). Evidence from in vitro translation studies has revealed that these two structurally distinct domains are generated by separate trimerization events (18).…”

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confidence: 99%

Hsp90 Phosphorylation Is Linked to Its Chaperoning Function

Zhao

Gilmore

Leone

et al. 2001

Journal of Biological Chemistry

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Studies on Hsp90 have mainly focused on its involvement in the activation of several families of protein kinases and of steroid hormone receptors. Little is known regarding the role of Hsp90 in the folding of nascent proteins. We previously reported that Hsp90 plays an active role in the posttranslational assembly of the C-terminal globular head of the reovirus attachment protein 1. We show here that Hsp90 becomes phosphorylated in this process. However, only the unphosphorylated form of Hsp90 is complexed with 1, suggesting that Hsp90 phosphorylation is coupled to the release of the chaperone from the target protein. Geldanamycin, which blocks 1 maturation by preventing the release of Hsp90 from 1, also inhibits Hsp90 phosphorylation. Taken together, these results demonstrate that Hsp90 phosphorylation is linked to its chaperoning function.

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Reovirus protein σ1: From cell attachment to protein oligomerization and folding mechanisms

Lee

Leone

1994

BioEssays

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The reovirus cell attachment protein sigma 1 is a lollipop-shaped structure with the fibrous tail anchored to the virion. Since it interacts with the cell receptor, sigma 1 is a major determinant of reovirus infectivity and tissue tropism. Studies on its structure-function relationships have been facilitated by the fact that protein sigma 1 produced in any expression system is capable of binding to cell receptors. The use of site-specific and deletion mutants has led to the identification and characterization of its virion anchorage and receptor binding domains. Studies on the oligomeric status of sigma 1 have revealed that sigma 1 is a homotrimer and that two independent trimerization events at different loci (the N- and C-terminal halves, respectively) of the protein, are involved in its generation. This also accounts for a clearly demonstrable dominant negative effect by a mutant subunit in a wild-type/mutant sigma 1 heterotrimer. Current efforts are focused on the involvement of chaperones in the generation of sigma 1 and on events that take place upon sigma 1 binding to the cell receptor. Protein sigma 1 has therefore become an excellent model system for the study of both virus attachment and protein oligomerization and folding mechanisms.

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The cell attachment proteins of type 1 and type 3 reovirus are differentially susceptible to trypsin and chymotrypsin

Cited by 38 publications

References 29 publications

Identification of Carbohydrate-Binding Domains in the Attachment Proteins of Type 1 and Type 3 Reoviruses

Identification of Carbohydrate-Binding Domains in the Attachment Proteins of Type 1 and Type 3 Reoviruses

Hsp90 Phosphorylation Is Linked to Its Chaperoning Function

Reovirus protein σ1: From cell attachment to protein oligomerization and folding mechanisms

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