Cooperative Interactions in Energy-dependent Accumulation of Ca2+ by Isolated Rat Liver Mitochondria

Bygrave, Fyfe L.; Reed, Ken C.; Spencer, T.

doi:10.1038/newbio230089a0

Cited by 62 publications

(23 citation statements)

References 10 publications

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“…Measurements of uptake velocity carried out on several mitochondrial types (Bygrave et al, 1971;Scarpa and Graziotti, 1973) have yielded sigmoidal kinetics, with maximal values varying between 0.1 and 0.6 µmol per mg of prot per min at 25°C, indicating positive cooperativity (with Hill coefficients at about ~2.0). The search for the uniporter has been very intensive, but has yielded essentially no results.…”

Section: History and Properties Of The Ca 2+ Transport Processmentioning

confidence: 99%

Generation, Control, and Processing of Cellular Calcium Signals

Carafoli

Santella

Branca

et al. 2001

Critical Reviews in Biochemistry and Molecular Biology

480

321

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In the course of evolution, Ca2+ has emerged as the most versatile intracellular messenger. Its concentration within cells is controlled by reversible binding to specific classes of proteins that act as Ca2+ sensors to decode its information before passing it on to targets. The decoding operation is based on specific conformational changes in the sensor proteins. Other proteins intrinsic to membranes simply control Ca2+ concentration without processing its message, by transporting it across membrane boundaries. They are located in the plasma membrane and in the membranes of the organelles (the endo(sarco)plasmic reticulum, the mitochondria, the nuclear envelope), which play distinctive roles in the cellular homeostasis of Ca2+. Ca2+ is an ambivalent signaling agent. It carries information to virtually all processes important to cell life (e.g., it couples excitation to contraction, secretion, gene transcription, and controls enzyme activity through protein phosphorylation-dephosphorylation), but also transmits signals that promote the programmed demise of cells. When escaping control, Ca2+ also precipitates toxic cell death.

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Section: History and Properties Of The Ca 2+ Transport Processmentioning

confidence: 99%

Generation, Control, and Processing of Cellular Calcium Signals

Carafoli

Santella

Branca

et al. 2001

Critical Reviews in Biochemistry and Molecular Biology

480

321

View full text Add to dashboard Cite

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“…The MCU is blocked by ruthenium red (RuR) and a colorless ruthenium red derivative, Ru360 (25, 26). The MCU has activation and a transport site for Ca 2+ , thus exhibiting second order kinetics (27–29). Despite the wealth of pharmacologic and electrophysiological data describing the MCU, the molecular identity of the channel is still unknown.…”

Section: Mitochondrial Ca2+ Dynamicsmentioning

confidence: 99%

Crosstalk signaling between mitochondrial Ca2+ and ROS

Feissner

Skalska²,

Gaum³

et al. 2009

Front Biosci

370

280

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Mitochondria are central to energy metabolism as the source of much of the cell’s ATP, as well as being a hub for cellular Ca2+ signaling. Mitochondrial Ca2+ is a positive effector of ATP synthesis, yet Ca2+ overload can lead to mitochondrial dysfunction and cell death. Moreover, Ca2+ uptake by mitochondria is involved in shaping cellular Ca2+ dynamics by regulating the concentrations of Ca2+ within microdomains between mitochondria and sarco/endoplasmic reticulum and plasma membrane Ca2+ transporters. Reactive oxygen species (ROS) generated as a consequence of ATP production in the mitochondria are important for cellular signaling, yet contribute to oxidative stress and cellular damage. ROS regulate the activity of redox sensitive enzymes and ion channels within the cell, including Ca2+ channels. For both Ca2+ and ROS, a delicate balance exists between the beneficial and detrimental effects on mitochondria. In this review we bring together current data on mitochondrial Ca2+ uptake, ROS generation, and redox modulation of Ca2+ transport proteins. We present a model for crosstalk between Ca2+ and ROS signaling pathways within mitochondrial microdomains.

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“…the number that gives the order of transport) of the uniporter gave sigmoidal plots of transport velocity vs [Ca 2+ ] and showed that the mechanism was second order in [Ca 2+ ] [47, 48]. While there was some controversy over the value of 2 for the Hill coefficient, that value is generally accepted today partly because it is also strongly supported by the results of Vinogradov and Scarpa showing that the uniporter has both a transport site and a separate activation site [49].…”

Section: Characteristics Of the Influx Mechanisms: The Uniportermentioning

confidence: 99%

Characteristics and possible functions of mitochondrial Ca2+ transport mechanisms

Gunter

Sheu

2009

Biochimica et Biophysica Acta (BBA) - Bioenergetics

194

204

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Mitochondria produce around 92% of the ATP used in the typical animal cell by oxidative phosphorylation using energy from their electrochemical proton gradient. Intramitochondrial free Ca2+ concentration ([Ca2+]m) has been found to be an important component of control of the rate of this ATP production. In addition, [Ca2+]m also controls the opening of a large pore in the inner mitochondrial membrane, the permeability transition pore (PTP), which plays a role in mitochondrial control of programmed cell death or apoptosis. Therefore, [Ca2+]m can control whether the cell has sufficient ATP to fulfill its functions and survive or is condemned to death. Ca2+ is also one of the most important second messengers within the cytosol, signaling changes in cellular response through Ca2+ pulses or transients. Mitochondria can also sequester Ca2+ from these transients so as to modify the shape of Ca2+ signaling transients or control their location within the cell. All of this is controlled by the action of four or five mitochondrial Ca2+ transport mechanisms and the PTP. The characteristics of these mechanisms of Ca2+ transport and a discussion of how they might function are described in this paper.

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Cooperative Interactions in Energy-dependent Accumulation of Ca2+ by Isolated Rat Liver Mitochondria

Cited by 62 publications

References 10 publications

Generation, Control, and Processing of Cellular Calcium Signals

Generation, Control, and Processing of Cellular Calcium Signals

Crosstalk signaling between mitochondrial Ca2+ and ROS

Characteristics and possible functions of mitochondrial Ca2+ transport mechanisms

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