A possible involvement of virus-associated protease in the fusion of sendai virus envelopes with human erythrocytes

Israel, S. Leon; Ginsberg, D.; Laster, Yehudith; Zakai, Nehama; Milner, Yoram; Loyter, Abraham

doi:10.1016/0005-2736(83)90049-4

Cited by 40 publications

(20 citation statements)

References 17 publications

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“…Thus, it is obvious that limited lysis of the membrane proteins offers favorable conditions for electrofusion. This is consistent with the observations that pretreatment of hen erythrocytes with proteinase enhanced the polyethylene glycol-induced fusion (Hartmann et al, 1976) and that the virus-associated protease is involved in the Sendal virus-induced fusion of human erythrocytes (Israel et al, 1983).…”

Section: Effects Of Phospholipases and Proteasessupporting

confidence: 81%

Electric pulse-induced fusion of mouse lymphoma cells: Roles of divalent cations and membrane lipid domains

Ohno‐Shosaku

Okada

1985

J. Membrain Biol.

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Mouse leukemic lymphoblasts (L5178Y) brought into close contact by dielectrophoresis underwent cell fusion following the application of electrical pulses in the presence of electrolytes. The electrically fused cells became spherical after switching off the dielectrophoretic field. Fusion between a cell vitally stained with Janus Green and that with Neutral Red resulted in the homokaryon with a mixed color. Intracellular potentials simultaneously recorded from the two cells located on both sides of the homokaryon were identical. The fusion efficiency was remarkably dependent upon temperature, displaying a discontinuity at about 11 degrees C in the Arrhenius plot. The extracellular application of phospholipase-A2 or -C suppressed the fusion yield. Thus, it appears that the phospholipid domains play a crucial role in the electric pulse-induced cell fusion. Treatment of the cells with proteolytic enzymes markedly enhanced the fusion yield, presumably due to removing the glycocalix and/or giving rise to fusion-potent, protein-free lipid domains. The presence of millimolar concentrations of divalent cations (irrespective of Mg2+ or Ca2+) as well as of micromolar concentrations of Ca2+ (but not Mg2+) was prerequisite to the resealing of membranes suffered from electrical breakdown upon exposure to electric pulses. In addition, extracellular Ca2+ (but not Mg2+) ions at more than micromolar concentrations were indispensable for the cell fusion.

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Section: Effects Of Phospholipases and Proteasessupporting

confidence: 81%

Electric pulse-induced fusion of mouse lymphoma cells: Roles of divalent cations and membrane lipid domains

Ohno‐Shosaku

Okada

1985

J. Membrain Biol.

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“…It was suggested earlier that proteolytic enzymes may be involved in the fusion process at neutral pH (29). This is consistent with serine protease-like activity associated with Sendai virus and its reconstituted envelopes (Fand HN-virosomes) with both F and HN glycoproteins (21). We have recently established that Sendai virus F protein in F-virosomes can induce complete membrane fusion, provided that the latter are bound tightly to the target cell membrane (5,9,23).…”

supporting

confidence: 82%

A 45,000-M(r) glycoprotein in the Sendai virus envelope triggers virus-cell fusion

Kumar

Hassan

Tyagi

et al. 1997

J Virol

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Sendai virus envelopes devoid of hemagglutinin-neuraminidase but containing the fusion protein (F-virosomes) were prepared. F-virosomes exhibited discernible serine protease activity at neutral pH. Electrophoretic analysis of the protein profile of the F-virosomes under nonreducing conditions, by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing, led to the identification of a previously unknown glycoprotein with a relative molecular weight of 45,000 (45K protein) associated with the F protein. The identity of the 45K protein, as distinct from F protein, was established by Western blot analysis with F-and 45K-specific antibodies. This 45K protein forms a nexus with the F protein through noncovalent hydrophobic interactions, as proved by its sensitivity to urea treatment, and it is essential for the proteolytic activity of the F-virosomes as well as for the fusion of the viral envelope with host cell membrane. N-terminal sequence analysis (first 11 amino acids) of this protein showed strong homology (>90%) to flavivirus NS3 serine proteases but no similarity to any of the Sendai viral proteins. On the basis of the N-terminal sequence, oligonucleotides were designed corresponding to the sense and antisense DNA sequences. Dot blot hybridization and primer extension with these oligonucleotides with the viral and the host genome confirmed the host origin of this protein. Further, the limited proteolytic digestion of the target membrane resulted in significant inhibition of viral fusion with it. On the basis of these results, we postulate a model for the molecular mechanism of F protein-induced membrane fusion, which may provide a rationale for other paramyxoviruses.

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“…(iv) When fusion occurs before lysis, either polycells or polyghosts are formed depending on the experimental conditions [56]. These observations, coupled with the presence in the virus of both a hydrophobic peptide that is believed to perturb lipid bilayers [58] and a protease [27], are consistent with the proposed osmotic mechanism for cell fusion.…”

Section: Some Applications Of the Modelsupporting

confidence: 71%

“…There is evidence, however, that proteinases are also important in fusion induced by poly(ethylene glycol) [26]. It has been suggested that proteolytic activity associated with the Sendai virus is an integral feature of its ability to fuse cells [27], and a metalloendoprotease is important in the fusion of myoblasts into myotubes [28]. In electrically induced cell fusion, the breakdown pulse appears to damage the membrane skeleton, since an unusually high diffusion constant for dipoles in the plane of the membranes of electrically fused cells has been observed.…”

Section: Perturbation Of Membrane Proteinsmentioning

confidence: 99%

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1986

FEBS Letters

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A possible involvement of virus-associated protease in the fusion of sendai virus envelopes with human erythrocytes

Cited by 40 publications

References 17 publications

Electric pulse-induced fusion of mouse lymphoma cells: Roles of divalent cations and membrane lipid domains

Electric pulse-induced fusion of mouse lymphoma cells: Roles of divalent cations and membrane lipid domains

A 45,000-M(r) glycoprotein in the Sendai virus envelope triggers virus-cell fusion

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