Fluorogenic Probe for Constitutive Cellular Endocytosis

SummaryEndocytosis is a fundamental process of eukaryotic cells that is critical for nutrient uptake, signal transduction, and growth. We have developed a molecular probe to quantify endocytosis. The probe is a lipid conjugated to a fluorophore that is masked with an enzyme-activatable moiety known as the trimethyl lock. The probe is not fluorescent when incorporated into the plasma membrane of human cells but becomes fluorescent upon internalization into endosomes, where cellular esterases activate the trimethyl lock. Using this probe, we found that human breast cancer cells undergo constitutive endocytosis more rapidly than do matched noncancerous cells. These data reveal a possible phenotypic distinction of cancer cells that could be the basis for chemotherapeutic intervention.

Graphical AbstractFigure optionsDownload high-quality image (189 K)Download as PowerPoint slideHighlights
► A lipid-based probe, lipid 1, for continuous monitoring of endocytosis in live cells is reported
► Lipid 1 was shown to report only on new endocytic events
► Lipid 1 reports on the rate of endocytosis
► Cancerous and noncancerous cell lines from the same patient have different endocytosis rates