Regulation of Calcium Signaling by the Intrinsic Cell Death Pathway in C. elegans

University Of Rochester, Rochester NY

Investigators

Abstract

Calcium, and regulating its concentration, are essential for life. Changes in calcium concentration are used to convey diverse types of information within cells (intracellular calcium signaling). The particular physiological outputs of calcium signaling cascades are exquisitely dependent upon spatial and temporal constraints. A variety of proteins help to shape calcium signals, and in mammals this regulation can be extremely complex. The nematode worm Caenorhabditis elegans is a model organism that is widely used for genetic approaches and exhibits many of the same constraints on calcium signaling as mammals. The use of this model allows researchers to circumvent the complexities of mammalian systems and more directly show cause and effect through advanced genomic editing approaches and integrative physiology. Specifically, this project will investigate how the interaction between two classes of proteins that are central to calcium signaling regulates physiological and behavioral outputs. The Nehrke Lab is strongly committed to promoting community interactions and diversity in science and to training the next generation of scientists. Toward these ends, the project will continue to provide STEM education to Rochester City School District third-graders through an outreach program at the YMCA and will initiate a joint training program with Monroe Community College that allows students to rotate among a variety of University of Rochester Medical Center laboratories during the academic year and then to undertake a ten-week summer research fellowship in one of those labs. The inositol 1, 4, 5-trisphosphate receptor (IP3R) is an endoplasmic reticular (ER) Ca2+ release channel whose activity is central to Ca2+ signaling. Fine-tuning of IP3R activity by other proteins diversifies its signaling repertoire. Recent evidence indicates that anti-apoptotic Bcl-2 family members interact with the IP3R and that this may facilitate ER-to-mitochondrial Ca2+ transfer to promote oscillatory Ca2+ signaling rather than apoptotic Ca2+ overload. In mammals, studying the role of IP3R/Bcl-2 interactions is complicated by multiple IP3R isoforms and Bcl-2 family members that share contact sites with the receptor, making it difficult to address specific cause and effect. In contrast, C. elegans has only a single isoform of each protein, which nevertheless perform similar functions and possess nearly identical amino acid sequences to their mammalian counterparts at the sites of interaction. Sophisticated genetic tools, including CRISPR-Cas9 mediated genome editing to create "loss-of-interaction" models and cutting-edge approaches using biosensors to measure localized calcium signaling, will be used to test this hypothesis and to interrogate the underlying mechanisms. Research results will increase understanding of inter-organelle communication and its relevance to normal physiology. The award supports a successful and long-standing outreach program aimed at Rochester City School District third-grade students, who are among the most impoverished in the country. In addition, a new initiative will synergize with existing local infrastructure to create shadowing and summer research traineeships for underrepresented Monroe Community College students continuing on to four-year universities. Research training for a postdoctoral fellow and mentoring experience for two graduate students will also be provided. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.