PBIO SEMINAR SERIES

Mitochondrial regulation of arterial calcium signals: mechanisms and functional consequences

Wednesday - May 09, 2007
06-07 Seminar Series
T-435

Jonathan Jaggar
Associate Professor University of Tennessee
Speaker's website

Host: Santana

Arterial diameter is regulated by distinct local and global intracellular calcium (Ca2+) signals that occur in smooth muscle cells. Mechanisms that regulate these different Ca2+ signals and the functional consequences of such modulation are poorly understood. In particular, Ca2+ signal regulation by mitochondria is unclear. I will present evidence that mitochondria regulate both local and global intracellular Ca2+ signals in arterial smooth muscle cells through pathways that include permeability transition pore opening and reactive oxygen species (ROS) generation. Data indicate that mitochondria-derived ROS dilate cerebral arteries by activating localized Ca2+ signals termed “calcium sparks”, and that antihypertensive ATP-sensitive K+ channel openers induce vasodilation by stimulating this pathway. In addition, I will introduce the concept that small and large mitochondrial depolarizations lead to differential regulation of ROS, Ca2+ spark activity, and thus arterial diameter.