Is macropinocytosis more than just a passive gulp?

Abstract

Macropinocytosis is known as nonselective drinking of the cellular milieu for scavenging of nutrients and uptake of extracellular fluids. It has recently gained attention in cancer research, as targeting the uptake of nutrients or chemotherapeutic particles by tumor cells holds promise for new therapeutic interventions. Macropinocytic cups form from actin-based protrusions that coalesce into cups and collapse into large vesicles containing cargoes and transmembrane receptors, which can then be degraded in lysosomes or recycled back to the plasma membrane. How macropinocytosis is triggered and the various ways that cells utilize cargoes are topics of much interest. Here, we discuss emerging evidence that cargo or membrane receptor uptake in macropinocytosis may in some cases be selective and may substantially alter cell surface receptor trafficking and display.