TY - JOUR
T1 - The role of low pH and disulfide shuffling in the entry and fusion of Semliki Forest virus and Sindbis virus
AU - Glomb-Reinmund, Sallie
AU - Kielian, Margaret
N1 - Funding Information:
We thank Anna Ahn for technical assistance, the members of our laboratory for helpful discussions and suggestions, and Dr. Duncan Wilson and the members of our laboratory for critical reading of the manuscript. We thank Dr. Richard Kuhn of Purdue University for providing Toto 1101, sequence information, and helpful suggestions. This work was supported by grants to M.K. from the Public Health Service (GM52929), by the Hirschl Charitable Trust, by the Jack K. and Helen B. Lazar fellowship in Cell Biology, and by Cancer Center Core Support Grant NIH/NCI P30-CA13330. S.G.-R. was supported by NIH Training Grant 2T32 CA09173-15. Data in this paper are from a thesis submitted in partial fulfillment of the requirements for the Degree of Doctor of Philosophy in the Sue Golding Graduate Division of Medical Sciences, Albert Einstein College of Medicine, Yeshiva University.
PY - 1998/9/1
Y1 - 1998/9/1
N2 - Semliki Forest virus (SFV), an enveloped alphavirus, infects cells via a membrane fusion reaction that is induced by the low pH in endocytic vesicles. The role of low pH in the entry of the alphavirus Sindbis virus (SIN) is unclear, and an alternative fusion mechanism involving receptor-induced disulfide bond rearrangements at neutral pH has been proposed. The entry properties of SFV and SIN were here compared in parallel using treatment with the weak base NH4Cl or the vacuolar ATPase inhibitors bafilomycin A-1 or concanamycin to neutralize endosome pH. Three membrane impermeant thiol modifying reagents, 5,5'-dithio-bis(2-nitrobenzoic acid) (DTNB), ρ- chloromercuriphenylsulfonic acid (pCMBS), and monobromotrimethylammoniobimane (Thiolyte MQ), were used to inhibit thiol-disulfide exchange reactions. Primary infection by both SFV and SIN was inhibited by neutralization of endosome pH using NH4Cl, bafilomycin, or concanamycin. The concentration of NH4Cl or bafilomycin required for inhibition correlated with the pH dependence of membrane fusion for SFV, SIN, and a pH-shift mutant of SFV. SFV and SIN infection were partially inhibited by the thiol blocker DTNB, but not by pCMBS or Thiolyte MQ. Our data suggest that acidic endosomal pH induces the fusion activity of both SFV and SIN during virus infection.
AB - Semliki Forest virus (SFV), an enveloped alphavirus, infects cells via a membrane fusion reaction that is induced by the low pH in endocytic vesicles. The role of low pH in the entry of the alphavirus Sindbis virus (SIN) is unclear, and an alternative fusion mechanism involving receptor-induced disulfide bond rearrangements at neutral pH has been proposed. The entry properties of SFV and SIN were here compared in parallel using treatment with the weak base NH4Cl or the vacuolar ATPase inhibitors bafilomycin A-1 or concanamycin to neutralize endosome pH. Three membrane impermeant thiol modifying reagents, 5,5'-dithio-bis(2-nitrobenzoic acid) (DTNB), ρ- chloromercuriphenylsulfonic acid (pCMBS), and monobromotrimethylammoniobimane (Thiolyte MQ), were used to inhibit thiol-disulfide exchange reactions. Primary infection by both SFV and SIN was inhibited by neutralization of endosome pH using NH4Cl, bafilomycin, or concanamycin. The concentration of NH4Cl or bafilomycin required for inhibition correlated with the pH dependence of membrane fusion for SFV, SIN, and a pH-shift mutant of SFV. SFV and SIN infection were partially inhibited by the thiol blocker DTNB, but not by pCMBS or Thiolyte MQ. Our data suggest that acidic endosomal pH induces the fusion activity of both SFV and SIN during virus infection.
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U2 - 10.1006/viro.1998.9275
DO - 10.1006/viro.1998.9275
M3 - Article
C2 - 9721245
AN - SCOPUS:0032169169
SN - 0042-6822
VL - 248
SP - 372
EP - 381
JO - Virology
JF - Virology
IS - 2
ER -