Mitochondria structure and position in the local control of calcium signals in smooth muscle cells

McCarron, John G. and Saunter, Christopher and Wilson, Calum and Girkin, John M. and Chalmers, Susan; Trebak, Mohamed and Earley, Scott, eds. (2018) Mitochondria structure and position in the local control of calcium signals in smooth muscle cells. In: Signal Transduction and Smooth Muscle. CRC Press, Boca Raton, Florida, pp. 173-190. ISBN 9781498774222 (https://doi.org/10.1201/b20699-9)

[thumbnail of McCarron-etal-crcpress-Mitochondria-structure-and-position-in-the-local-control]
Preview
Text. Filename: McCarron_etal_crcpress_Mitochondria_structure_and_position_in_the_local_control.pdf
Final Published Version

Download (1MB)| Preview

Abstract

In smooth muscle mitochondria are major regulators of contractility, proliferation and growth through the organelles' control of cytoplasmic Ca2+ concentrations. Mitochondria regulate cytoplasmic Ca2+ over concentrations of the ion that range from 200nM – 50 µM. An acknowledged feature of the organelle’s ability to control Ca2+ over the higher Ca2+ concentrations (>10 µM) is the position and structure of the organelles at sites near ion channels. However, the precise relationship between Ca2+ signalling and mitochondria is preliminary in large part because the structure and position of the organelles is not well understood. We recently developed methods to determine the structure and position of each mitochondrion and the entire organelle complement in live, fully-differentiated cells smooth muscle cells. In fully differentiated smooth muscle, mitochondria are distributed through the cytoplasm mainly as spherical or short rod shaped structures (mean length 0.9 µm). Mitochondrial Ca2+ uptake regulates Ca2+ release from IP3R clusters. However, the organelles do not appear to regulate the gating of voltage-dependent Ca2+ channels on the plasma membrane. Nonetheless the position of mitochondria correlates with an increased magnitude of voltage-dependent Ca2+ entry. Voltage-dependent Ca2+ channel expression or distribution, or both, may be regulated by mitochondria.