PhD Student Research

Cytoskeleton-based Delivery of Ion Channels in the Heart
Principal Investigator: Rachel Baum, PhD Candidate
Project Summary

A major unanswered question in Cell Biology, also relevant to developing future therapeutics, is how membrane proteins are trafficked to their appropriate location on the cell surface. We know a lot about the machinery that gets them there, but less about how the specificity of delivery is determined.

Our model to understand trafficking specificity is the Connexin 43 gap junction protein. Connexin 43 is essential to most cells to allow ions and small molecules to be passed between cells. In the heart, Connexin 43 gap junctions are necessary for synchronized muscle contraction, for the heart to work as one organ, during each heartbeat. A primary cause of death in patients with heart disease is less Connexin 43 at cell-cell borders and subsequent malignant, often fatal, ventricular arrhythmias.

My research focuses specifically on how GJA1-20k, an internally translated isoform of Connexin 43, organizes the cytoskeleton to direct the intracellular trafficking of newly synthesized Connexin 43 protein from inside the cell to specific locations on the cell border.

Expected Outcomes

This work will resolve a major mystery in protein regulation. For the heart, it will open the door to therapeutics, which can restore gap junction trafficking in disease, limiting the arrhythmias of sudden cardiac death.

PhD Candidate Profile

Rachel Baum is from the San Francisco Bay Area and graduated from the University of California, San Diego (UCSD), with a degree in biochemistry and cell biology. During her undergraduate studies, she gained experience through several industry internships in chemistry labs. After graduating, she worked at Vertex Pharmaceuticals as a research associate in a neurobiology lab, studying Huntington's disease. She then worked as a research associate in an immunology lab at UCSD, studying the role of type 2 innate lymphoid cells in allergic inflammation.

Rachel is currently a PhD candidate at Cedars-Sinai and is doing her thesis research in the Smidt Heart Institute. Under the joint mentorship of Drs. Robin Shaw and Ting-Ting Hong, she is studying the role of the cytoskeleton in intracellular protein trafficking.

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