Fatima Garza Ramon

Diabetes is a chronic condition that impacts the lives of over 10.5% of adults worldwide and is only expected to increase. Life with diabetes often leads to kidney failure, heart disease, amputations and more, which are difficult progressions to impede with current medications. Within the past 20 years, kinases have become a popular target for drug discovery for clinical diseases like diabetes. Despite the favor of kinase-centered therapeutics, much of the human kinome remains understudied. A serine/threonine kinase, MAP3K15, is one of these understudied “dark kinases,” which are clinically relevant kinases prioritized for further study. Recently, MAP3K15 was found to be a possible obesity-independent therapeutic target for diabetes. Therefore, researching MAP3K15 kinase can provide insight into its biochemical functions within the cell and begin the consideration of its therapeutic relevance. In order to investigate MAP3K15, the SERIOHL (serine-oriented human library-kinase library reactions) method was used with the purpose of determining its preferred phosphorylation sites, preferred amino acid sequence motifs, and potential substrates. In this approach, a library of peptide sequences that consist of -15 to +15 range of more than 100,000 serine sites that are known to be phosphorylated in the human proteome was expressed and purified. The library was subjected to MAP3K15 in an in-vitro kinase reaction for its phosphorylation. Using LC-MS/MS and bioinformatics, sequence preferences and substrates of MAP3K15 kinase were not significantly recognized due to low phosphorylation scores and absence of phosphopeptide across kinase replicates. Despite a lack of data, three possible substrates were detected, PIKFYVE, STATH, and PCLO, which prompt further exploration and repetition of the experiment. Further research will be required in order to fulfill the partial characterization of MAP3K15 with SERIOHL for the ultimate goal of understanding its cellular and physiological roles in diabetes.