Fig. 8. Hypothetical model of integrin transport and the clustering at FCs. Surface integrins are first internalized, probably by endocytosis (1), and accumulated around the nucleus; this occurs 30 minutes to 1 hour after plating the cell. Integrins are transported to the ventral side of the cell by an actomyosin-dependent vesicle transport system (2) and are recruited to the tip of extending FC, probably via exocytosis (3) (red arrows show the sequence of these events). The direction of FC elongation in this study was towards the cell centre in most observations (the direction is shown by blue arrow). Elongation ceased when FCs grew to 7 µm.