Human Osteosarcoma with mEmerald-MAP4 and mCherry-Rab5a
VEGFR2 is a receptor tyrosine kinase. Its function is to regulate vascular physiology. VEGFR2-mediated regulation of endothelial function is reliant on varying but specific Rab-mediated GTP hydrolysis activity necessary for trafficking of the endosomes. The human osteosarcoma cells (U-2 line) featured in the digital video sequences in this section are visualized expressing mCherry fused to Rab5a and mEmerald fused to MAP4, highlighting endosomes and the intracellular microtubule network.
The red fluorescent protein utilized to visualize endosomes, mCherry, is one of the most useful members of the mFruit series of fluorescent proteins that were created through the directed evolution of mRFP1. Excitation and emission maxima of mCherry occur at 587 and 610 nanometers, respectively. The green fluorescent protein employed, mEmerald, is a high-performance variant of EGFP. Both the brightness and photostability of mEmerald are superior to that of EGFP. Peak excitation of mEmerald occurs at 487 nanometers and peak emission takes place at 509 nanometers.