Single-particle tracking of murine polyoma virus-like particles on live cells and artificial membranes

Ewers, Helge; Smith, Alicia E.; Sbalzarini, Ivo F.; Lilie, Hauke; Koumoutsakos, Petros; Helenius, Ari

doi:10.1073/pnas.0504407102

Cited by 251 publications

(274 citation statements)

References 40 publications

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“…experimental values with diffusion on solid-supported lipid bilayers formed from the fusion of single unilamellar vesicles of these same lipids (8) and found slower diffusion for bilayers, a 2-dimensional diffusion D ϭ 0.01 m 2 ⅐s Ϫ1 , which agrees with literature (9). Although it is true that diffusion on the supported bilayer is expected to be slower than diffusion along the tubes owing to friction from the solid substrate underneath, such reduction is expected to be on the order of a factor of 2, the amount that friction from the supporting substrate reduces diffusion in supported bilayers compared with free-standing giant unilamellar vesicles (10).…”

Section: Resultssupporting

confidence: 80%

Anomalous yet Brownian

Wang

Anthony

Bae

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

453

550

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We describe experiments using single-particle tracking in which mean-square displacement is simply proportional to time (Fickian), yet the distribution of displacement probability is not Gaussian as should be expected of a classical random walk but, instead, is decidedly exponential for large displacements, the decay length of the exponential being proportional to the square root of time. The first example is when colloidal beads diffuse along linear phospholipid bilayer tubes whose radius is the same as that of the beads. The second is when beads diffuse through entangled F-actin networks, bead radius being less than one-fifth of the actin network mesh size. We explore the relevance to dynamic heterogeneity in trajectory space, which has been extensively discussed regarding glassy systems. Data for the second system might suggest activated diffusion between pores in the entangled F-actin networks, in the same spirit as activated diffusion and exponential tails observed in glassy systems. But the first system shows exceptionally rapid diffusion, nearly as rapid as for identical colloids in free suspension, yet still displaying an exponential probability distribution as in the second system. Thus, although the exponential tail is reminiscent of glassy systems, in fact, these dynamics are exceptionally rapid. We also compare with particle trajectories that are at first subdiffusive but Fickian at the longest measurement times, finding that displacement probability distributions fall onto the same master curve in both regimes. The need is emphasized for experiments, theory, and computer simulation to allow definitive interpretation of this simple and clean exponential probability distribution.diffusion ͉ fluorescence ͉ imaging ͉ probability distribution ͉ actin T he supposition that Brownian motion follows Gaussian statistics is seldom tested experimentally. In fact, there are few physical situations in which the statistics of displacement distribution can be measured directly. More often, one simply verifies that mean-square displacement is proportional to time, which defines a diffusion coefficient, D. However, a finite diffusion coefficient does not necessarily stem from a Gaussian distribution, because D only holds information regarding second-order cumulants but not the full probability distribution of displacements (1). Relaxation functions in Fourier space are also heavily relied upon in experimental tests of theories that assume Gaussian statistics, but the limited signal-to-noise ratio in measuring these quantities does not typically allow one to deduce distribution functions in real space with the large dynamic range presented by the experiments described below. It is easy to show formally that other zero-centered distributions than Gaussian, in particular exponentially decaying probability distributions of displacement amplitude, would also lead formally to meansquared displacement proportional to time.Here, using single-particle tracking (2), we report the full displacement probability during Brownian m...

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Section: Resultssupporting

confidence: 80%

Anomalous yet Brownian

Wang

Anthony

Bae

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

453

550

View full text Add to dashboard Cite

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“…With this technique, the individual steps of the entry process and the dynamics of these processes can be elucidated. SVT has been utilized to investigate the entry and trafficking of several viruses including adeno-associated virus (Bräuchle et al 2002;Seisenberger et al 2001), adenovirus (Suomalainen et al 1999), simian virus 40 (Damm et al 2005), murine polyoma virus (Ewers et al 2005), HIV (McDonald et al 2002), influenza virus (Lakadamyali et al 2003;Rust et al 2004), rabies virus (Finke et al 2004) and murine leukemia virus (Lehmann et al 2005). From the trajectories of individual viruses, the interactions between these particles and different cellular components can be directly observed.…”

Section: Introductionmentioning

confidence: 99%

HIV-1–cellular interactions analyzed by single virus tracing

et al. 2008

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Single virus tracing (SVT) allows the direct investigation of the entry pathway of viruses into living cells. Using fluorescently labeled virus-like particles (VLPs) and SVT, we have studied the interaction between human immunodeficiency virus type 1 (HIV-1) and the plasma membrane of living cells. From the trajectories of freely diffusing VLPs in solution, we established that the particle preparation was homogeneous and the particles had a hydrodynamic radius of 86 ± 5 nm, consistent with the size of single HI viruses. The VLPs that come in contact with the cell surface either become immobilized or rapidly dissociate from the cell surface. The fraction of virions that become immobilized on the plasma membrane correlates with the surface heparan sulfate linked proteoglycans (HSPG) concentration of the cell line tested. The particles that are not immobilized make an average of 1.5 contacts with the cell surface before diffusing away. For most cell lines investigated, the contact duration follows an exponential distribution with a lifetime between 20 and 50 ms depending on the cell type.

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“…In supported membrane bilayers, the viruses are highly mobile, no confinement is observed (Ewers et al 2005;Kukura et al 2009). However, an exception can be observed when the bilayer contains high amounts of GM1 (1 mol %).…”

Section: Association Of Gsls and Ligands With Lipid Domainsmentioning

confidence: 99%

“…Single particle tracking has shown that when incoming mPy viruses bind to the PM of cells, they first undergo random lateral movement for 5 -15 sec with a diffusion constant of 0.01 mm 2 /sec (Ewers et al 2005). The permanent or transient loss of mobility after the initial phase of free diffusion depends on the actin cytoskeleton.…”

Section: Association Of Gsls and Ligands With Lipid Domainsmentioning

confidence: 99%