Maturation cleavage of the murine leukemia virus Env precursor separates the transmembrane subunits to prime it for receptor triggering

Robin Löving, Shang Rung Wu, Mathilda Sjöberg, Birgitta Lindqvist, Henrik Garoff

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The Env protein of murine leukemia virus matures by two cleavage events. First, cellular furin separates the receptor binding surface (SU) subunit from the fusion-active transmembrane (TM) subunit and then, in the newly assembled particle, the viral protease removes a 16-residue peptide, the R-peptide from the endodomain of the TM. Both cleavage events are required to prime the Env for receptor-triggered activation. Cryoelectron microscopy (cryo-EM) analyses have shown that the mature Env forms an open cage-like structure composed of three SU-TM complexes, where the TM subunits formed separated Env legs. Here we have studied the structure of the R-peptide precursor Env by cryo-EM. TM cleavage in Moloney murine leukemia virus was inhibited by amprenavir, and the Envs were solubilized in Triton X-100 and isolated by sedimentation in a sucrose gradient. We found that the legs of the R-peptide Env were held together by trimeric interactions at the very bottom of the Env. This suggested that the R-peptide ties the TM legs together and that this prevents the activation of the TM for fusion. The model was supported by further cryo-EM studies using an R-peptide Env mutant that was fusion-competent despite an uncleaved R-peptide. The Env legs of this mutant were found to be separated, like in the mature Env. This shows that it is the TM leg separation, normally caused by R-peptide cleavage, that primes the Env for receptor triggering.

Original languageEnglish
Pages (from-to)7735-7740
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number20
DOIs
Publication statusPublished - 2012 May 15

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Murine Leukemia Viruses
Leg
Cryoelectron Microscopy
Furin
env Gene Products
Moloney murine leukemia virus
Octoxynol
R peptide
Virion
Sucrose
Peptide Hydrolases
Peptides

All Science Journal Classification (ASJC) codes

  • General

Cite this

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title = "Maturation cleavage of the murine leukemia virus Env precursor separates the transmembrane subunits to prime it for receptor triggering",
abstract = "The Env protein of murine leukemia virus matures by two cleavage events. First, cellular furin separates the receptor binding surface (SU) subunit from the fusion-active transmembrane (TM) subunit and then, in the newly assembled particle, the viral protease removes a 16-residue peptide, the R-peptide from the endodomain of the TM. Both cleavage events are required to prime the Env for receptor-triggered activation. Cryoelectron microscopy (cryo-EM) analyses have shown that the mature Env forms an open cage-like structure composed of three SU-TM complexes, where the TM subunits formed separated Env legs. Here we have studied the structure of the R-peptide precursor Env by cryo-EM. TM cleavage in Moloney murine leukemia virus was inhibited by amprenavir, and the Envs were solubilized in Triton X-100 and isolated by sedimentation in a sucrose gradient. We found that the legs of the R-peptide Env were held together by trimeric interactions at the very bottom of the Env. This suggested that the R-peptide ties the TM legs together and that this prevents the activation of the TM for fusion. The model was supported by further cryo-EM studies using an R-peptide Env mutant that was fusion-competent despite an uncleaved R-peptide. The Env legs of this mutant were found to be separated, like in the mature Env. This shows that it is the TM leg separation, normally caused by R-peptide cleavage, that primes the Env for receptor triggering.",
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Maturation cleavage of the murine leukemia virus Env precursor separates the transmembrane subunits to prime it for receptor triggering. / Löving, Robin; Wu, Shang Rung; Sjöberg, Mathilda; Lindqvist, Birgitta; Garoff, Henrik.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 109, No. 20, 15.05.2012, p. 7735-7740.

Research output: Contribution to journalArticle

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T1 - Maturation cleavage of the murine leukemia virus Env precursor separates the transmembrane subunits to prime it for receptor triggering

AU - Löving, Robin

AU - Wu, Shang Rung

AU - Sjöberg, Mathilda

AU - Lindqvist, Birgitta

AU - Garoff, Henrik

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