The Ratio of Plasma Membrane Cholesterol to Phospholipid and the Inhibition of Sindbis Virus Maturation by Low NaCl Medium

Garry, Robert F.; Bostick, Denise A.; Schram, Richard; Waite, Marilynn R. F.

doi:10.1099/0022-1317-66-5-1171

Cited by 15 publications

(5 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The high speed MV pellet from control cells had a cholesterol to phospholipid ratio of 0.092 ± 0.047 (mean ± sem), while the ratio for MV shed from SLO- or PFO-challenged cells was 0.296 ± 0.049 and 0.363 ± 0.040, respectively (p = 0.0398 and 0.012 vs control by ANOVA). Values for MV from SLO- or PFO-challenged BMDM are consistent with previous measurements of the cholesterol to phosopholipid ratio for the plasma membrane 63 , 64 . Also consistent with previous results 16 , β-Actin was present in all three fractions following treatment with cytotoxic CDCs (Fig.…”

Section: Resultssupporting

confidence: 90%

Cholesterol-dependent cytolysins impair pro-inflammatory macrophage responses

Bhattacharjee

Keyel

2018

Sci Rep

View full text Add to dashboard Cite

Necrotizing soft tissue infections are lethal polymicrobial infections. Two key microbes that cause necrotizing soft tissue infections are Streptococcus pyogenes and Clostridium perfringens. These pathogens evade innate immunity using multiple virulence factors, including cholesterol-dependent cytolysins (CDCs). CDCs are resisted by mammalian cells through the sequestration and shedding of pores during intrinsic membrane repair. One hypothesis is that vesicle shedding promotes immune evasion by concomitantly eliminating key signaling proteins present in cholesterol-rich microdomains. To test this hypothesis, murine macrophages were challenged with sublytic CDC doses. CDCs suppressed LPS or IFNγ-stimulated TNFα production and CD69 and CD86 surface expression. This suppression was cell intrinsic. Two membrane repair pathways, patch repair and intrinsic repair, might mediate TNFα suppression. However, patch repair did not correlate with TNFα suppression. Intrinsic repair partially contributed to macrophage dysfunction because TLR4 and the IFNγR were partially shed following CDC challenge. Intrinsic repair was not sufficient for suppression, because pore formation was also required. These findings suggest that even when CDCs fail to kill cells, they may impair innate immune signaling responses dependent on cholesterol-rich microdomains. This is one potential mechanism to explain the lethality of S. pyogenes and C. perfringens during necrotizing soft tissue infections.

show abstract

Section: Resultssupporting

confidence: 90%

Cholesterol-dependent cytolysins impair pro-inflammatory macrophage responses

Bhattacharjee

Keyel

2018

Sci Rep

View full text Add to dashboard Cite

show abstract

“…For example, positive charges near the membrane interface will attract counterions to the interfacial region, and the counterion pressure opposes the local interfacial tension, resulting in a local lowering of the outer leaflet's interfacial tension. In this connection, Garry et al (16) have shown that budding is inhibited in BHK-S and CE cells incubated in low NaCl medium. Alternatively, the spike protein might act in the same fashion as the peptides cardiotoxin and melittin, which associate with specific lipid types to produce a local bending moment (17).…”

Section: Discussionmentioning

confidence: 95%

How does a virus bud?

Lerner¹,

Oster²

1993

Biophysical Journal

View full text Add to dashboard Cite

How does a virus bud from the plasma membrane of its host? Here we investigate several possible rate-limiting processes, including thermal fluctuations of the plasma membrane, hydrodynamic interactions, and diffusion of the glycoprotein spikes. We find that for bending moduli greater than 3 x 10(-13) ergs, membrane thermal fluctuations are insufficient to wrap the viral capsid, and the mechanical force driving the budding process must arise from some other process. If budding is limited by the rate at which glycoprotein spikes can diffuse to the budding site, we compute that the budding time is 10-20 min, in accord with the experimentally determined upper limit of 20 min. In light of this, we suggest some alternative mechanisms for budding and provide a rationale for the observation that budding frequently occurs in regions of high membrane curvature.

show abstract

“…Alphaviruses are spread by mosquitoes and have a variety of mammalian hosts, including man ( , ). Factors known to influence alphavirus budding efficiency include ionic strength conditions ( − ), plasma membrane cholesterol content ( − ), glycoprotein palmitoylation ( − ), lateral protein−protein interactions between the glycoproteins E2 and E1 ( − ), and protein−protein interactions between an assembled intracellular nucleocapsid and the cytoplasmic domain of E2 (cdE2) ( − ).…”

mentioning

confidence: 99%

Association of Sindbis Virus Capsid Protein with Phospholipid Membranes and the E2 Glycoprotein: Implications for Alphavirus Assembly

et al. 2005

View full text Add to dashboard Cite

A late stage in assembly of alphaviruses within infected cells is thought to be directed by interactions between the nucleocapsid and the cytoplasmic domain of the E2 protein, a component of the viral E1/E2 glycoprotein complex that is embedded in the plasma membrane. Recognition between the nucleocapsid protein and the E2 protein was explored in solution using NMR spectroscopy, as well as in binding assays using a model phospholipid membrane system that incorporated a variety of Sindbis virus E2 cytoplasmic domain (cdE2) and capsid protein constructs. In these binding assays, synthetic cdE2 peptides were reconstituted into phospholipid vesicles to simulate the presentation of cdE2 on the inner leaflet of the plasma membrane. Results from these binding assays showed a direct interaction between a peptide containing the C-terminal 16 amino acids of the cdE2 sequence and a Sindbis virus capsid protein construct containing amino acids 19-264. Additional experiments that probed the sequence specificity of this cdE2-capsid interaction are also described. Further binding assays demonstrated an interaction between the 19-264 capsid protein and artificial vesicles containing neutral or negatively charged phospholipids, while capsid protein constructs with N-terminal truncations displayed either little or no affinity for such vesicles. The membrane-binding property of the capsid protein suggests that the membrane may play an active role in alphavirus assembly. The results are consistent with an assembly process involving an initial membrane association, whereby an association with E2 glycoprotein further enhances capsid binding to facilitate membrane envelopment of the nucleocapsid for budding. Collectively, these experiments elucidate certain requirements for the binding of Sindbis virus capsid protein to the cytoplasmic domain of the E2 glycoprotein, a critical event in the alphavirus maturation pathway.

show abstract

The Ratio of Plasma Membrane Cholesterol to Phospholipid and the Inhibition of Sindbis Virus Maturation by Low NaCl Medium

Cited by 15 publications

References 29 publications

Cholesterol-dependent cytolysins impair pro-inflammatory macrophage responses

Cholesterol-dependent cytolysins impair pro-inflammatory macrophage responses

How does a virus bud?

Association of Sindbis Virus Capsid Protein with Phospholipid Membranes and the E2 Glycoprotein: Implications for Alphavirus Assembly

Contact Info

Product

Resources

About