Drawing on work from the Lawrence and Allbritton groups, we use cell-penetrating peptides (e.g. TAT) to deliver peptide substrates to cells. Our initial efforts focused on Abl and Syk tyrosine kinases (in collaboration with Jean Wang, UCSD and Robert Geahlen, Purdue University, respectively) producing the Abl full-length biosensor peptide (termed Abl-FL biosensor) and the Syk artificial substrate peptide (SAStide). We sometimes include protein-protein interaction ligands (such as the Abl SH3 ligand sequence P40) in order to modulate kinase binding, phosphorylation efficiency and, potentially, selectivity. Expanded substrate design projects involve using combination in silico/empirical workflows to develop novel peptide substrates for virtually any kinase. These first aimed to develop substrates for lanthanide luminescence assays, but can be adapted to any read-out strategy desired.

These projects have been funded by the NIH through a K99/R00 award (grant K99/R00CA127161), a R33 grant (R33CA183671) from the NCI Innovative Molecular Analysis Technologies (IMAT) program, and a R01 grant (R01CA182543), and by the Purdue University College of Pharmacy and Center for Cancer Research.