Fig. 1

Confocal microscopy image of membrane labelled (CellMask© Orange) U87 glioblastoma cells. TNTs are the fine straight structures which interconnect cells, clear TNTs are marked by yellow arrows. Other fine structures which do not have cell-to-cell contact are filopodia (blue arrows). Magenta arrows point to structures which are not distinguishable between not yet fused TNTs and filopodia. U87 glioblastoma cells have a high frequency of TNTs. Scale bar 50 μm