Real-time monitoring of transferrin-induced endocytic vesicle formation by mid-infrared surface plasmon resonance

Victor Yashunsky, Simcha Shimron, Vladislav Lirtsman, Aryeh M. Weiss, Naomi Melamed-Book, Michael Golosovsky, Dan Davidov, Benjamin Aroeti

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

We report on the application of surface plasmon resonance (SPR), based on Fourier transform infrared spectroscopy in the mid-infrared wavelength range, for real-time and label-free sensing of transferrin-induced endocytic processes in human melanoma cells. The evanescent field of the mid-infrared surface plasmon penetrates deep into the cell, allowing highly sensitive SPR measurements of dynamic processes occurring at significant cellular depths. We monitored in real-time, infrared reflectivity spectra in the SPR regime from living cells exposed to human transferrin (Tfn). We show that although fluorescence microscopy measures primarily Tfn accumulation in recycling endosomes located deep in the cell's cytoplasm, the SPR technique measures mainly Tfn-mediated formation of early endocytic organelles located in close proximity to the plasma membrane. Our SPR and fluorescence data are very well described by a kinetic model of Tfn endocytosis, suggested previously in similar cell systems. Hence, our SPR data provide further support to the rather controversial ability of Tfn to stimulate its own endocytosis. Our analysis also yields what we believe is novel information on the role of membrane cholesterol in modulating the kinetics of endocytic vesicle biogenesis and consumption.

Original languageEnglish
Pages (from-to)1003-1012
Number of pages10
JournalBiophysical Journal
Volume97
Issue number4
DOIs
StatePublished - 19 Aug 2009
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics

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