Daniel J. Donoghue
Provost, Sixth College; Professor, Chemistry & Biochemistry
Ph.D., Massachusetts Institute of Technology
I have a long-standing interest in Receptor Tyrosine Kinases (RTKs), a passion which evolved from my graduate work at MIT with Phil Sharp, Bob Weinberg and David Baltimore, and from my postdoctoral work in Tony Hunter's lab at the Salk Institute. During the past decade, my research interests have also included some non-RTK projects (e.g. cyclin B and cyclin-like proteins such as Spy1, co-discovered in our lab).
More recently, I decided to focus on the Fibroblast Growth Factor Receptor (FGFR) family of RTKs and their roles in oncogenic and inflammatory signaling pathways, exploiting proteomic and genomic approaches such as mass spec analysis of proteins, and microarray analysis of gene expression to identify novel regulatory phosphorylation sites, protein-protein interactions, and gene interaction networks.
My group has investigated the role of FGFR4 and FGFR2 in the regulation of the Nuclear Factor kappaB (NFkappaB) inflammatory signaling pathway. Signaling regulated by NFκB is important to many inflammatory and autoimmune diseases, cancer, and stress responses. The kinase that directly regulates the canonical NFκB transcriptional pathway, Inhibitor of κB kinase beta (IKKβ), undergoes activation by Ser phosphorylation in response to inflammatory signals. We have demonstrated a direct interaction between IKKβ and FGFR4 and FGFR2. Using titanium dioxide-based phosphopeptide enrichment (TiO2)-liquid chromatography (LC)-high mass accuracy tandem mass spectrometry (MS/MS), we analyzed IKKβ phosphorylation in human cells expressing IKKβ and FGFR2 and identified an abundant site of Tyr phosphorylation at Tyr169 within the Activation Loop of IKKβ. The phosphomimic at this site confers a level of kinase activation and NFκB nuclear localization exceeding the iconic mutant S177E/S181E, demonstrating that RTK-mediated Tyr phosphorylation of IKKβ has the potential to directly regulate NFκB transcriptional activation.
We are also extensively studying specific mutations of IKKβ that have been identified in Multiple Myeloma, Spleen Marginal Zone Lymphoma and Mantle Cell Lymphoma. Our current research shows that mutation at a specific residue leads to constitutive activation of IKKb and increased ubiquitination. Through a combination of mass spectroscopy and cell biological experiments we have identified a novel K63-linked ubiquitination site in IKKb. These results will have extensive ramifications for understanding inflammatory signaling and devising new therapeutics that target these pathways.The occurrence of a chromosomal translocation can result in the formation of two genes fused together such that, when translated, a fusion protein results and is often oncogenic. FGFR fusion proteins are increasingly being detected in a variety of cancers. Particularly, a fusion protein of FGFR3 and transforming acidic coiled-coil containing 3(TACC3) has been identified in glioblastoma, bladder cancer, lung cancer, oral cancer, head and neck cancer, and gallbladder cancer. In this fusion, as with almost all FGFR fusion proteins, it is presumed the partner protein provides a dimerization domain, allowing the FGFR fusion to dimerize and constitutively activate. Our lab is currently exploring the nature of this activation and its oncogenic signaling.
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