CUR - The Council on Undergraduate Research

Interactions between T-Cell Death Associated Gene 51 (TDAG51) and Tubby

Aurora Emini, Christopher Williams, Lorena Samentar, Arnold Salazar, Dr. Peipei Pan and Dr. Nora B. Caberoy, School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154 Dr. Nora Caberoy, Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154 Lorena Samentar, University of the Philippines in the Visayas, Miag-ao, Iloilo, Philippines Dr. Peipei Pan, School of Medicine, University of California, San Francisco, 1001 Potrero Ave, San Francisco, California 94110

Tubby is an important protein found within the brain and retina. Mutations within the genes of this protein can lead to retinal degeneration, hearing loss, or delayed-onset obesity. However, the exact mechanism of how these disease phenotypes results from tubby mutation is unknown. One way of elucidating these mechanisms is by looking at Tubby’s interactions with other proteins. Previously, the Caberoy Lab has identified T-Cell Death-Associated Gene 51 (TDAG51) as a putative protein that binds to Tubby using open reading frame phage display. TDAG51, also known as Pleckstrin Homology-Like Domain Family A member 1 (PHLDA1), is a pro-apoptotic gene in T-cell receptor-mediated cell death and is implicated in mature onset obesity, hepatic steatosis, insulin resistance, and enhanced reactive oxygen species production. TDAG51 has a conserved pleckstrin homology (PH) domain that has been shown to bind with lipids, proteins, and other intracellular signaling molecules. To verify the interaction of TDAG51 and Tubby and to investigate the importance of the PH domain, we cloned TDAG51 and TDAG51 with PH domain deletion and did in vivo assay by co-immunoprecipitation. We successfully cloned TDAG51 and TDAG51 with a deletion of the PH domain and verified through Western blot analysis and DNA sequencing. Co-immunoprecipitation assay showed that TDAG51 binds to Tubby. This TDAG51-Tubby interaction was abolished with the deletion of the PH domain of TDAG51. Studies on subcellular localization of TDAG51 and its co-localization with Tubby using immunohistochemical methods are currently underway. Additional information regarding Tubby and TDGA51 interactions can potentially lead to groundbreaking discoveries about the pathways they participate in. This is important towards understanding the mechanisms as to how their mutations result in disease phenotypes. Hopefully, this will ultimately reveal pathways or molecular players that can be used as targets in the development of therapies for retinal degeneration, hearing loss, and obesity.

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