The domain localization at both ends of the confined GUVs is reminiscent to the polarization that can be observed in some cellular processes. To further quantify this analogy, we developed an image analysis process where each confined GUV detected by fluorescence microscopy was arbitrarily oriented in a top/bottom fashion and segmented into 4 areas of equal length along the longitudinal axis, enabling the definition of a "pole" and a "body" area on each half of the GUV (Figure , top right).