Target type: biologicalprocess
A process in which a calcium ion (Ca2+) is transported from the cytosol into the mitochondrial matrix. [GOC:vw]
Calcium import into mitochondria is a tightly regulated process crucial for maintaining cellular homeostasis and signaling pathways. The process involves the movement of calcium ions (Ca2+) from the cytosol, the fluid surrounding the cell's organelles, into the mitochondrial matrix, the innermost compartment of the mitochondria. This movement is facilitated by specialized protein complexes embedded in the mitochondrial membranes.
The primary pathway for calcium import is through the mitochondrial calcium uniporter (MCU). This protein complex forms a channel in the inner mitochondrial membrane, allowing Ca2+ to flow down its electrochemical gradient from the cytosol into the matrix. The MCU is highly selective for Ca2+ and exhibits a rapid rate of transport, enabling mitochondria to rapidly respond to changes in cytosolic Ca2+ levels.
The activity of the MCU is regulated by a complex interplay of factors, including:
* **Mitochondrial membrane potential:** The electrochemical gradient across the inner mitochondrial membrane is essential for MCU activity. A more negative potential within the matrix drives Ca2+ import.
* **Cytosolic Ca2+ concentration:** The rate of Ca2+ import is directly proportional to the concentration of Ca2+ in the cytosol.
* **Regulatory proteins:** Several proteins have been identified that modulate MCU activity. For example, MICU1 and MICU2 act as gatekeepers, controlling the permeability of the channel to Ca2+.
Once inside the mitochondrial matrix, Ca2+ plays a critical role in various processes, including:
* **ATP production:** Ca2+ activates enzymes involved in the tricarboxylic acid (TCA) cycle, a key pathway for ATP synthesis.
* **Mitochondrial biogenesis:** Ca2+ influences the expression of genes involved in the synthesis of new mitochondrial components.
* **Apoptosis:** High levels of Ca2+ within the mitochondria can trigger programmed cell death.
Overall, calcium import into mitochondria is a highly dynamic and tightly regulated process that is essential for maintaining cellular function and signaling. Disruptions in this process can lead to a range of diseases, including neurodegenerative disorders and cancer.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Inositol 1,4,5-trisphosphate receptor type 1 | An inositol 1,4,5-trisphosphate receptor type 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q14643] | Homo sapiens (human) |
| Stress-70 protein, mitochondrial | A stress-70 protein, mitochondrial that is encoded in the genome of human. [PRO:DAN] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| inositol 1,4,5-trisphosphate | Inositol 1,4,5-Trisphosphate: Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4,5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1,4,5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell's endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin. | myo-inositol trisphosphate | mouse metabolite |
| (((4-nitrophenyl)amino)(2,2,4,4-tetramethyl thiochroman-6-yl)amino) methane-1-thione |