Abstract by Chrissy Egbert
Tsz Yin Chan
Chemistry and Biochemistry
A ubiquitin mediated mechanism of TNK1 activity and stability
TNK1 is a poorly characterized non-receptor protein tyrosine kinase (NRTK) with potential oncogenic function. We do not yet understand the mechanisms that regulate TNK1 signaling, activity and stability. TNK1 possesses a unique protein domain organization. Specifically, it contains a C-terminal ubiquitin association (UBA) domain that is uncommon in NRTKs. We discovered that this UBA domain helps regulate TNK1 activity and stability. The removal of the TNK1 UBA domain leads to an increase in TNK1 kinase activity and overall TNK1 protein levels. Using predictive protein modeling we identified several important residues for ubiquitin association. Mutation of these residues leads to the loss of ubiquitin binding and a corresponding increase in TNK1 kinase activity. Finally, we identified TNK1 mutations in primary human cancers that disrupt the TNK1 UBA domain, suggesting that loss of TNK1 Ubiquitin binding may be a foundational oncogenic event in human cancer.