A CycloRGDf(Me-V) Analog as Chemical Probe to Study Integrins Function in Living Cells

We report a chemical probe that can be used to image integrins in living cells. The fluorescent probe was derived from cyclo-RGDf(Me-V), a compound selective for integrins that possess an RGD-binding domain. We describe its synthesis and we demonstrate its use to detect integrin αVβ5 in cells. The probe’s dissociation constant for the integrin αVβ5 protein is 0.18 μM. The probe's activity was validated in murine BV-2 microglial cells using cell engulfment assays, flow cytometry, and confocal fluorescence imaging. This probe will provide access to spatiotemporally resolved studies of RGD-binding integrin function in living cells without the need for genetic modification.