VEGF（vascular endothelial growth factor）is a kind of ligand commonly used in research. It has various functions like increasing vascular permeability and promoting extracellular matrix degeneration. Using BBa_K2886007, you can express and purify VEGF-165 which is most commonly used subtype of VEGF easily and construct receptors (BBa_K2886002 or BBa_K2886003) that could recognize VEGF-165 efficiently. BBa_K2886001 is TEV protease functioning as inner-membrane domain that can recognize specific peptide sequence and cut it and then release transcription factors as a result for instance. BBa_K2886000 is transmembrane linker combining the outer-membrane domain and inner-membrane domain together to become a whole.

With this part collection and appropriate transcription factor, you could construct your own STEP system to recognize almost anything soluble you want（like VEGF as we do）and start the downstream reactions.