(full paper is archived in the Miller Library)
Title: TRPM7: a pathway for zinc influx
Student Author(s): Rustagi, Arjun
Faculty Advisor(s): Thompson, Stuart
Location: Final Papers Biology 176H
Date: June 2004
Abstract: Zinc is an essential metabolic heavy metal in all cells. Zinc imbalances in the brain are considered a cause of neurodegenerative disorders. A member of the TRPM cation channel family, TRPM7 is a widely-expressed outwardly-rectifying Ca2+ and Mg2+ channel through which trace metal ions like Zn2+ flow into cells. TRPM7 Ca2+ permeation may be essential for cell viability. While previous characterizations of Zn2+ permeation involved mM levels of Zinc, here we show that TRPM7 is the dominant Zn2+ pathway in HEK-293 cells at 100 mM Zn2+. We performed confocal microscope imaging experiments with the Zn2+ -binding fluorophore FluoZin-3 AM. In the presence of 100 mMZn2+, HEK-293 cells overexpressing murine TRPM7 load ZN2+ almost 20% more than normal HEK-293 cells. Data for experiments in the presence of physiological levels of Ca2+ and Mg2+ were compared to data for experiments performed in the absence of Ca2+ and Mg2+, indicating that the presence of 2 mM Ca2+ and 2 mM Mg2+ inhibited Zn2+ influx.