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Direct observation of membrane insertion by enveloped virus matrix proteins by phosphate displacement.

Neuman BW, Kiss G, Al-Mulla HM, Dokland T, Buchmeier MJ, Weikl T, Schley D - PLoS ONE (2013)

Bottom Line: Enveloped virus release is driven by poorly understood proteins that are functional analogs of the coat protein assemblies that mediate intracellular vesicle trafficking.We used differential electron density mapping to detect membrane integration by membrane-bending proteins from five virus families.This demonstrates that virus matrix proteins replace an unexpectedly large portion of the lipid content of the inner membrane face, a generalized feature likely to play a role in reshaping cellular membranes.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Reading, Reading, Berkshire, United Kingdom. b.w.neuman@reading.ac.uk

ABSTRACT
Enveloped virus release is driven by poorly understood proteins that are functional analogs of the coat protein assemblies that mediate intracellular vesicle trafficking. We used differential electron density mapping to detect membrane integration by membrane-bending proteins from five virus families. This demonstrates that virus matrix proteins replace an unexpectedly large portion of the lipid content of the inner membrane face, a generalized feature likely to play a role in reshaping cellular membranes.

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Related in: MedlinePlus

Apparent electron density is constant for small and large virus particles.The virion edge was sampled at four positions described in Fig. 3 (In, Core, Matrix, Glycoprotein) and at the background ice beyond the Glycoprotein (Ice). Each datapoint shows the average density for 8 samples from 12 Tacaribe virus particles of similar size. Error bars indicate standard deviation.
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pone-0057916-g004: Apparent electron density is constant for small and large virus particles.The virion edge was sampled at four positions described in Fig. 3 (In, Core, Matrix, Glycoprotein) and at the background ice beyond the Glycoprotein (Ice). Each datapoint shows the average density for 8 samples from 12 Tacaribe virus particles of similar size. Error bars indicate standard deviation.

Mentions: We had two main concerns regarding phosphate displacement. The first was mechanical – as the virus gets smaller, the membrane curves more per unit area. Large and small particles differ in curvature per unit length, which could change how many lipid molecules the electron beam encounters at the particle edge, causing large particles to appear brighter than small particles. We tested for this effect by examining the intensity of internal, membrane and external features of 216 Tacaribe virus particles, which ranged from 40 nm to 260 nm in diameter (Fig. 4). Image intensity did not vary noticeably over the virus size range, demonstrating that curvature does not have a noticeable effect on intensity for virus-sized membranes.


Direct observation of membrane insertion by enveloped virus matrix proteins by phosphate displacement.

Neuman BW, Kiss G, Al-Mulla HM, Dokland T, Buchmeier MJ, Weikl T, Schley D - PLoS ONE (2013)

Apparent electron density is constant for small and large virus particles.The virion edge was sampled at four positions described in Fig. 3 (In, Core, Matrix, Glycoprotein) and at the background ice beyond the Glycoprotein (Ice). Each datapoint shows the average density for 8 samples from 12 Tacaribe virus particles of similar size. Error bars indicate standard deviation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585246&req=5

pone-0057916-g004: Apparent electron density is constant for small and large virus particles.The virion edge was sampled at four positions described in Fig. 3 (In, Core, Matrix, Glycoprotein) and at the background ice beyond the Glycoprotein (Ice). Each datapoint shows the average density for 8 samples from 12 Tacaribe virus particles of similar size. Error bars indicate standard deviation.
Mentions: We had two main concerns regarding phosphate displacement. The first was mechanical – as the virus gets smaller, the membrane curves more per unit area. Large and small particles differ in curvature per unit length, which could change how many lipid molecules the electron beam encounters at the particle edge, causing large particles to appear brighter than small particles. We tested for this effect by examining the intensity of internal, membrane and external features of 216 Tacaribe virus particles, which ranged from 40 nm to 260 nm in diameter (Fig. 4). Image intensity did not vary noticeably over the virus size range, demonstrating that curvature does not have a noticeable effect on intensity for virus-sized membranes.

Bottom Line: Enveloped virus release is driven by poorly understood proteins that are functional analogs of the coat protein assemblies that mediate intracellular vesicle trafficking.We used differential electron density mapping to detect membrane integration by membrane-bending proteins from five virus families.This demonstrates that virus matrix proteins replace an unexpectedly large portion of the lipid content of the inner membrane face, a generalized feature likely to play a role in reshaping cellular membranes.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Reading, Reading, Berkshire, United Kingdom. b.w.neuman@reading.ac.uk

ABSTRACT
Enveloped virus release is driven by poorly understood proteins that are functional analogs of the coat protein assemblies that mediate intracellular vesicle trafficking. We used differential electron density mapping to detect membrane integration by membrane-bending proteins from five virus families. This demonstrates that virus matrix proteins replace an unexpectedly large portion of the lipid content of the inner membrane face, a generalized feature likely to play a role in reshaping cellular membranes.

Show MeSH
Related in: MedlinePlus