Mitochondrial Ca2+ uptake pathways

作者：Elustondo Pia A; Nichols Matthew; Robertson George S; Pavlov Evgeny V

来源：Journal of Bioenergetics and Biomembranes, 2017, 49(1): 113-119.

DOI：10.1007/s10863-016-9676-6

• Mitochondria
• Calcium
• Ion channel
• Exchanger
• Uniporter
• Permeability transition pore
• Inorganic polyphosphate
• Polyhydroxybutyrate

Calcium (Ca2+) plays diverse roles in all living organisms ranging from bacteria to humans. It is a structural element for bones, an essential mediator of excitation-contraction coupling, and a universal second messenger in the regulation of ion channel, enzyme and gene expression activities. In mitochondria, Ca2+ is crucial for the control of energy production and cellular responses to metabolic stress. Ca2+ uptake by the mitochondria occurs by the uniporter mechanism. The Mitochondrial Ca2+ Uniporter (MCU) protein has recently been identified as a core component responsible for mitochondrial Ca2+ uptake. MCU knockout (MCU KO) studies have identified a number of important roles played by this high capacity uptake pathway. Interestingly, this work has also shown that MCU-mediated Ca2+ uptake is not essential for vital cell functions such as muscle contraction, energy metabolism and neurotransmission. Although mitochondrial Ca2+ uptake was markedly reduced, MCU KO mitochondria still contained low but detectable levels of Ca2+. In view of the fundamental importance of Ca2+ for basic cell signalling, this finding suggests the existence of other currently unrecognized pathways for Ca2+ entry. We review the experimental evidence for the existence of alternative Ca2+ influx mechanisms and propose how these mechanisms may play an integral role in mitochondrial Ca2+ signalling.

• 出版日期2017-2