Limits...
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.

Show MeSH

Related in: MedlinePlus

Phosphate signal dimming effects are visible over a wide range of focal distance.Average electron density is shown for images of Tacaribe virus particles, GP vesicles and associated vesicles that were recorded as defocus series. Data marked with an asterisk contributed to the TCRV line in Fig. 3.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585246&req=5

pone-0057916-g005: Phosphate signal dimming effects are visible over a wide range of focal distance.Average electron density is shown for images of Tacaribe virus particles, GP vesicles and associated vesicles that were recorded as defocus series. Data marked with an asterisk contributed to the TCRV line in Fig. 3.

Mentions: Secondly, we considered whether electron interference at the matrix-membrane interface could explain the decreased inner membrane phosphate signal. Contrast in electron microscopy images has two main sources, called amplitude and phase contrast. Amplitude contrast occurs when electrons collide with atoms in the sample and are scattered, and changes with the atomic mass of the sample [13]. Phase contrast is caused by electron interference, and changes with defocus [13]. To examine the effects of phase contrast, TCRV images were grouped according to defocus and analysed as before. Matrix-dependent phosphate displacement was observed across the defocus range (Fig. 5), though the effect was strongest in images where both phosphate rings were distinctly visible. We concluded that matrix-dependent displacement was not likely caused by electron interference.


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)

Phosphate signal dimming effects are visible over a wide range of focal distance.Average electron density is shown for images of Tacaribe virus particles, GP vesicles and associated vesicles that were recorded as defocus series. Data marked with an asterisk contributed to the TCRV line in Fig. 3.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0057916-g005: Phosphate signal dimming effects are visible over a wide range of focal distance.Average electron density is shown for images of Tacaribe virus particles, GP vesicles and associated vesicles that were recorded as defocus series. Data marked with an asterisk contributed to the TCRV line in Fig. 3.
Mentions: Secondly, we considered whether electron interference at the matrix-membrane interface could explain the decreased inner membrane phosphate signal. Contrast in electron microscopy images has two main sources, called amplitude and phase contrast. Amplitude contrast occurs when electrons collide with atoms in the sample and are scattered, and changes with the atomic mass of the sample [13]. Phase contrast is caused by electron interference, and changes with defocus [13]. To examine the effects of phase contrast, TCRV images were grouped according to defocus and analysed as before. Matrix-dependent phosphate displacement was observed across the defocus range (Fig. 5), though the effect was strongest in images where both phosphate rings were distinctly visible. We concluded that matrix-dependent displacement was not likely caused by electron interference.

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