A Message from Dr. Jim Mahoney:
My research is focused on the role of the E3 ubiquitin ligase UFD2 in development, regeneration, and autoimmune disease. We originally cloned UFD2 using an affinity-based approach to isolate novel autoantigens recognized by circulating antibodies in patients with systemic autoimmune disease. The ubiquitination pathway is primarily responsible for degradation of intracellular proteins that are either damaged or no longer needed, and is critical for temporally dependent processes such as the cell cycle. UFD2 is a member of the RING finger group of the E3 ligase family, a large family of enzymes that, in a manner analogous to protein kinases, recognize acceptor substrates and catalyze the transfer of ubiquitin onto those substrates.
We showed that while UFD2 is conserved throughout all eukaryotes, UFD2 in higher eukaryotes such as vertebrates contains a novel, highly conserved amino-terminal serine/threonine-rich domain, and that this domain is cleaved from the remainder of the molecule by caspases and granzyme B during apoptosis. In collaboration with Dr. Sarah Spinette in the lab, we have shown that this domain is highly phosphorylated during mitosis, and that cells with reduced UFD2 expression arrest at the cell cycle checkpoint between metaphase and anaphase and undergo apoptosis. These data strongly suggest that UFD2 plays a critical role during mitosis, and that its activity is controlled by phosphorylation within this amino terminal regulatory domain.
These data and other preliminary studies have led us to hypthesize a role for UFD2 in development and/or regeneration after injury. Moreover, we have found that UFD2 is an autoantigen in a subset of patients with the autoimmune disease scleroderma, which is characterized by a pathologic proliferation of fibroblasts in the skin and internal organs, a process that may be compared to overactive post-damage tissue regeneration.
Rheumatology Bioassay Core
I direct the Rheumatology Bioassay Core, a resource to aid investigators inside and outside the Division in establishing and performing mechanistic assays using patient-derived materials. We provide at low cost the expertise, equipment, and technical support necessary to perform a wide variety of bioassays, from commercially available ELISAs to custom-designed assays of patient samples at the level of the gene (e.g., quantitative RT-PCR), protein (western blotting, ELISA), or cell (flow cytometry, lymphocyte activation). We also perform a variety of sample preparation functions, such as purification of RNA and genomic DNA, and cryopreservation of peripheral blood mononuclear cells. We have established the infrastructure to process, catalog and store samples, as well as to interface with other Core facilities to facillitate high-throughput techniques such as SNP analysis and microarrays.
Jim Mahoney, Ph.D.
David is a technician working with Dr. Mahoney.