Extracellular matrix internalisation links nutrient signalling to invasive migration

Integrins are key mediators of cell-extracellular matrix (ECM) interaction, linking the ECM to the actin cytoskeleton. Beside localising at the cell surface, they can be internalised and transported back to the plasma membrane (recycled) or delivered to the late endosomes/lysosomes for degradation. We and others have shown that integrin can be endocytosed together with their ECM ligands. In this short review, I will highlight how extracellular protein (including ECM) endocytosis impinges on the activation of the mechanistic target of rapamycin (mTOR) pathway, a master regulator of cell metabolism and growth. This supports the intriguing hypothesis that ECM components may be considered as nutrient sources, primarily under soluble nutrient-depleted conditions.