Recycling and intracellular trafficking of VEGFR-2. In unstimulated endothelial cells (ECs), a significant proportion of VEGFR-2 is located in the EEA1⁺/Rab4⁺early/recycling endosomes. From this compartment, VEGFR-2 molecules could be recycled to the cell surface. Alternatively, a small portion of the receptor molecules could be transported to the CD63⁺late endosomes and eventually degraded in lyosomes. Upon VEGF stimulation, the VEGFR-2⁺vesicles stored in the EEA1⁺/Rab4⁺early/recycling endosomes are redistributed to the cell surface through the Src⁺recycling compartment and accumulated just beneath the plasma membrane (PM). VEGF stimulation also increases the distribution of VEGFR-2 in the late endosome compartment, where most of the receptor molecules are stored without further degradation.