(full paper is archived in the Miller Library)
Title: Calcium and magnesium flux via TRPM7
Student Author(s): Cribbs, Jennifer E.
Waters, Allison C.
Faculty Advisor(s): Thompson, Stuart
Location: Final papers Biology 176H
Date: June 2005
Abstract: Transient receptor potential melastatin 7 (TRPM7) is a widely expressed, constituatively active, voltage independent ion channel known to be permeable to most divalent and monovalent cations. TRPM7 may play an important role in Ca2+, Mg2+, and trace metal homeostasis. Our study examines the behavior of TRPM7 under physiologically relevant conditions. Confocal laser microscopy and the indicator dye fluo-3/AM allowed for visualization of intra cellular Ca2+ in response to changes in external Ca2+, indicating that TRPM7 functions as a calcium channel under physiologically appropriate conditions. Our results also indicated taht Mg2+ interferes with the movement of Ca2+ through the TRPM7 channel. The data further suggest that the percent of TRPM7 channels blocked by Mg2+ is proportional to the extracellular Mg2+ concentration. This implies a possible mechanism for ion permeation through TRPM7 that involves ion-ion interactions within the channel protein and implicates TRPM7 channels in Ca2+ and Mg2+ homeostasis.