This is important to note since vinculin recruitment to talin requires the stretching of talin. As a Pyrimethamine consequence, the vinculin, tensin and zyxin adapters are typically found in mature focal adhesions localized in lamella but not to lamellipodia, since adhesions maturation depends on myosin II driven tensile forces only once entering the lamellum. Finally, filopodia are known to contribute to the assembly of contractile bundles and substrate adhesions in the lamella, but how this process is influenced by the lamellipodia dynamic is not well understood. Although never addressed in the case of filopodia shaft adhesions, it has been demonstrated that the maturation of focal adhesions in the lamellum, is a myosin II-dependent process, but not that of nascent adhesions in the lamellipodium, and that focal adhesion maturation is coupled to the cycles of lamellipodium protrusions and retractions. The lamellipodium exhibits cycles of protrusions and retractions, whereby the protrusions are driven by the actin polymerization of the dendritic actin network at the leading edge of the lamellipodium while the retractions are initiated by actin-myosin II located in the lamellum just behind the lamellipodium-lamellum transition zone. The formation and dynamics of filopodia and lamellipodia are regulated by different GTPases, suggesting that the formation, maturation and turnover of the adhesions associated with these two types of cell edge protrusions serve different purposes. In fish fibroblasts, the appearance of filopodia adhesions, as recorded by paxillin recruitment, was observed to coincide with the advancement of the lamellipodium up to and past the respective adhesive segment of the filopodium. In keratinocytes, when reached by the advancing lamellipodia, nascent filopodia adhesions, visualized via different cytoplasmic adaptors and proximity to the substrate, increase their size along the former Tyrphostin AG 879 orientation of filopodia resulting in more matured substrate adhesions, a maturation process which has been proposed to be associated with increased traction forces.