CARMIL1-AA selectively inhibits macropinocytosis while sparing autophagy.

Macropinocytosis is reported to fuel tumor growth and drug resistance by allowing cancer cells to scavenge extracellular macromolecules. However, accurately defining the role of macropinocytosis in cancer depends on our ability to selectively block this process. 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) is widely used to inhibit macropinocytosis but affects multiple Na/H exchangers (NHE) that regulate cytoplasmic and organellar pH.