Fig. 2: Membrane packing determines the wetting affinity of biomolecular condensates. | Nature Communications

Fig. 2: Membrane packing determines the wetting affinity of biomolecular condensates.

From: Lipid packing and cholesterol content regulate membrane wetting and remodeling by biomolecular condensates

Fig. 2

a Representative confocal microscopy images of GUVs of the indicated lipids labeled with 0.1 mol% ATTO 647N-DOPE (green) in contact with glycinin condensates labeled with FITC-glycinin (magenta) at working conditions (150 mM NaCl, protein concentration 10 mg/mL, 23 ± 1 °C). Scale bars: 5 µm. b Sketch showing the parameters that define the geometric factor (\(\Phi\)). The three apparent contact angles \({\theta }_{i}\), \({\theta }_{e}\), and \({\theta }_{c}\) (observed microscopically), facing the vesicle interior (i), the external solution (e) and the condensate (c), are related to the three interfacial tensions occurring in the system, \({\Sigma }_{{ce}}\), \({\Sigma }_{{ie}}^{m}\), and \({\Sigma }_{{ic}}^{m}\). The three tensions are balanced at the three-phase contact line (black circle) forming the sides of a triangle45,48, as shown on the right. At the nanoscale, the membrane is smoothly curved and wetting is characterized by the intrinsic contact angle \({\theta }_{e}^{{in}}\); which is defined as \(\cos {\theta }_{e}^{{in}}=(\sin {\theta }_{e}-\sin {\theta }_{c})/\sin {\theta }_{i}\). The value of \({\theta }_{e}^{{in}}\) varies between 0° and 180° depending on the affinity of the condensate droplet for the membrane, as shown in the bottom in analogy to the behavior of liquid droplets at solid substrates. c Geometric factor (\(\Phi=(\sin {\theta }_{e}-\sin {\theta }_{c})/\sin {\theta }_{i}\), left axis) and affinity contrast (\(W={\Sigma }_{{ce}}/\Phi\), right axis) for the different membrane compositions characterizing the affinity of the condensate to the membrane. Individual data points are shown for each membrane composition. The lines indicate the mean value ± SD (n  =  7). d Intrinsic contact angle \({\theta }_{e}^{{in}}=\arccos \Phi\)45,48 for the different membrane compositions. Individual data points are shown for each membrane composition. The lines indicate the mean value ± SD (n  =  7). Source data are provided as a Source Data file.

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