Preparation of influenza virus subviral particles lacking the HA1 subunit of hemagglutinin: Unmasking of cross-reactive HA2 determinants

Graves, Peter N.; Schulman, Jerome L.; Young, James F.; Palese, Peter

doi:10.1016/0042-6822(83)90465-8

Cited by 131 publications

(94 citation statements)

References 22 publications

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“…Tryptic cleavage and reductive dissociation Two other criteria which distinguish the low pH conformation of HA from its native structure include the accessibility of specific sites to cleavage by trypsin (Skehel et al, 1982) and the loss of stabilizing interactions between the HAl and HA2 subunits (Graves et al, 1983). From the data shown in Figure 3A it is apparent that the HA on Rostock infected cells incubated with amantadine or on control cells exposed briefly to PBS-citrate pH 5.0 is similarly susceptible to specific digestion by trypsin.…”

Section: Resultsmentioning

confidence: 77%

Specific structural alteration of the influenza haemagglutinin by amantadine.

Sugrue¹,

Bahadur²,

Zambon³

et al. 1990

The EMBO Journal

209

186

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Amantadine hydrochloride specifically blocks the release of virus particles from H7 influenza virus infected cells. This appears to be the direct consequence of an amantadine induced change in the haemagglutinin (HA) to its low pH conformation. The effect is indirect and mediated via interaction of the drug with the M2 protein since mutants altered in this component alone are insensitive to amantadine. The tining of drug action, some 15-20 min after synthesis, and its coincidence with proteolytic cleavage indicates that the modifications to HA occur late during transport but prior to insertion into the plasma membrane. Reversal by mM concentrations of amines and 0.1 /M monensin indicates that amantadine action causes a reduction in intravesicular pH which triggers the conformational change in HA. We conclude, therefore, that the function of MN inhibited by amantadine is involved in counteracting the acidity of vesicular compartments of the exocytic pathway in infected cells and is important in protecting the structural integrity of the acid-sensitive glycoprotein.

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Section: Resultsmentioning

confidence: 77%

Specific structural alteration of the influenza haemagglutinin by amantadine.

Sugrue¹,

Bahadur²,

Zambon³

et al. 1990

The EMBO Journal

209

186

View full text Add to dashboard Cite

show abstract

“…The top of the HA monomer comprises an independently folded domain that includes about two-thirds of HA1 (Wiley and Skehel, 1987). HA1 can be released in folded form from mature HA by reduction of a disulfide bond (Graves et al, 1983). The third secreted fragment appeared to contain the sequences for the HA domain and the portion of HA2 that forms the actual stem domain.…”

Section: Discussionmentioning

confidence: 99%

Quality Control in the Secretory Pathway: The Role of Calreticulin, Calnexin and BiP in the Retention of Glycoproteins with C-Terminal Truncations

Zhang

Braakman

Matlack

et al. 1997

MBoC

183

104

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Unlike properly folded and assembled proteins, most misfolded and incompletely assembled proteins are retained in the endoplasmic reticulum of mammalian cells and degraded without transport to the Golgi complex. To analyze the mechanisms underlying this unique sorting process and its fidelity, the fate of C-terminally truncated fragments of influenza hemagglutinin was determined. An assortment of different fragments was generated by adding puromycin at low concentrations to influenza virus-infected tissue culture cells. Of the fragments generated, <2% was secreted, indicating that the system for detecting defects in newly synthesized proteins is quite stringent. The majority of secreted species corresponded to folding domains within the viral spike glycoprotein. The retained fragments acquired a partially folded structure with intrachain disulfide bonds and conformation-dependent antigenic epitopes. They associated with two lectin-like endoplasmic reticulum chaperones (calnexin and calreticulin) but not BiP/GRP78. Inhibition of the association with calnexin and calreticulin by the addition of castanospermine significantly increased fragment secretion. However, it also caused association with BiP/GRP78. These results indicated that the association with calnexin and calreticulin was involved in retaining the fragments. They also suggested that BiP/GRP78 could serve as a backup for calnexin and calreticulin in retaining the fragments. In summary, the results showed that the quality control system in the secretory pathway was efficient and sensitive to folding defects, and that it involved multiple interactions with endoplasmic reticulum chaperones.

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“…72 Unsurprisingly, antibodies to less-well conserved domains do not cross-react except for strains within a subtype. 73 Similar approaches to those described above have been used to a lesser extent to study the antigenic properties of NA. 25 The catalytic site, a large pocket of the distal surface formed by the tetramers, is surrounded by antigenic variable regions.…”

Section: Correlates Of Protectionmentioning

confidence: 99%