fig1

Figure 1. Formation mechanisms of EVs and TNTs. (A) EVs are generated via different pathways. Generation of exosomes require inner budding within EE maturing into MVBs, whereas ectosomes form via negative membrane curvature-induced budding at the plasma membrane. Both the tetraspanins CD9 and CD81 are components of ectosomal membranes and are found on TNTs. (B) TNTs can be formed via different mechanisms, viz. cell dislodgement (left panels), wherein cells that come in contact with each other leave behind a tubular connection when they move apart, and protrusion-elongation (right panels), where one cell, following negative membrane curvature, actively extends a protrusion towards a neighbouring cell to eventually form a functional connection.