GO:1902656 calcium ion import into cytosol: Transport Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1902656 (calcium ion import into cytosol) describes the directed movement of calcium ions (Ca2+) into the cytosol, the main intracellular signaling compartment.
• Cytosolic Ca2+ import is mediated by channels and transporters on the plasma membrane, endoplasmic reticulum, mitochondria, and lysosomes, and is balanced by export and buffering systems.
• Mitochondrial calcium uptake occurs through the mitochondrial calcium uniporter (MCU) complex and is driven by the mitochondrial membrane potential.
• Lysosomal calcium import depends on transporters such as TMEM165, which also regulates ion homeostasis and cell survival.
• In yeast, calcium import after an extracellular pulse is negatively regulated by calmodulin kinase 2 (Cmkl2) and Rch1p.
• Dysregulated cytosolic calcium import contributes to Huntington's disease pathology, where miR-34a-5p acts as a molecular hub.
Description
Calcium ion import into cytosol (GO:1902656) is the biological process defined as the directed movement of calcium ion into a cytosol. Cytosolic Ca2+ serves as a universal second messenger controlling secretion, contraction, gene expression, and cell survival, so the mechanisms that deliver Ca2+ to the cytosol are central to physiology. The process is not a single reaction but a coordinated set of transport events at multiple membranes, including the plasma membrane, endoplasmic reticulum (ER), mitochondria, and lysosomes. Because cytosolic Ca2+ concentration is kept very low at rest, import must be tightly coupled to export and buffering to avoid toxicity. Researchers study GO:1902656 to understand how cells decode Ca2+ signals and how defects in import contribute to disease. This article integrates the QuickGO definition with verified literature to summarize the genes, mechanisms, disease links, and experimental models relevant to calcium ion import into cytosol.
calcium ion import into cytosol At A Glance
| GO ID | GO:1902656 |
|---|---|
| GO term | calcium ion import into cytosol |
| Ontology | biological_process |
| Synonym | calcium import into cytosol |
| Definition | The directed movement of calcium ion into a cytosol. |
| Major function | Delivery of Ca2+ to the cytosol for signaling, secretion, contraction, and survival |
| Key compartments | Plasma membrane, endoplasmic reticulum, mitochondria, lysosomes |
| Representative mediators | MCU complex, TMEM165, Cmkl2/Rch1p, miR-34a-5p |
| Related process | Calcium export from cells and cytosolic Ca2+ buffering |
What Is GO:1902656?
GO:1902656 (calcium ion import into cytosol) is the directed movement of calcium ion into a cytosol. In practice, this means the translocation of Ca2+ from an extracellular space or from an intracellular organelle lumen into the cytosol, the soluble cytoplasmic compartment. The term covers import across the plasma membrane and release or transport from intracellular stores such as the ER, mitochondria, and lysosomes. It is a biological process and is distinct from calcium export, which moves Ca2+ out of the cytosol.
Why Is calcium ion import into cytosol Important in Cell Biology?
Calcium ion import into cytosol is fundamental because cytosolic Ca2+ controls nearly every aspect of cell behavior, from short-term secretion and contraction to long-term gene expression and cell death. The process must be spatially and temporally precise: mitochondria take up Ca2+ to tune energy metabolism and survival, the ER maintains ion homeostasis required for plasma membrane repair, and lysosomes use transporters such as TMEM165 to control ion balance and survival. In yeast, calcium import after an extracellular calcium pulse is negatively regulated by Cmkl2 and Rch1p, illustrating conserved feedback control. In plants, calcium and manganese transport across organellar compartments is similarly integrated with physiology. Defects in these pathways are linked to human disease, including Huntington's disease where miR-34a-5p acts as a pathomechanistic hub.
• Provides the Ca2+ signal that drives secretion, contraction, and gene expression.
• Supports mitochondrial metabolism and cell survival through mitochondrial Ca2+ uptake.
• Maintains ER ion homeostasis needed for plasma membrane repair.
• Controls lysosomal ion balance and cell survival via transporters such as TMEM165.
• Is negatively regulated in yeast by Cmkl2 and Rch1p after extracellular calcium pulses.
• Integrates calcium and manganese handling in plant organellar compartments.
• Is implicated in Huntington's disease through miR-34a-5p-dependent mechanisms.
• Is relevant to Sec61-channelopathies where ion homeostasis and protein translocation intersect.
• Provides targets for pharmacological and genetic manipulation of Ca2+ signaling.
• Serves as a model for studying organelle-specific ion transport.
What Happens During calcium ion import into cytosol?
Plasma membrane Ca2+ entry
In simple terms: Calcium enters the cytosol from outside the cell through channels in the plasma membrane.
The plasma membrane is the first route for calcium ion import into cytosol. Extracellular Ca2+ is abundant, while resting cytosolic Ca2+ is kept low, so opening of plasma membrane channels creates a steep inward gradient. This entry is balanced by export systems that remove Ca2+ from cells, preventing sustained overload. In yeast, an extracellular calcium pulse triggers import that is negatively regulated by Cmkl2 and Rch1p, showing that plasma membrane entry is subject to feedback control.
Mitochondrial Ca2+ uptake
In simple terms: Mitochondria take up calcium from the cytosol using a dedicated channel complex.
Mitochondria import Ca2+ into their matrix through the mitochondrial calcium uniporter (MCU) complex, driven by the mitochondrial membrane potential. Although this moves Ca2+ out of the cytosol, it is part of the broader cytosolic Ca2+ handling system because mitochondrial buffering shapes cytosolic Ca2+ transients. Mitochondrial Ca2+ uptake supports energy metabolism and can influence cell survival decisions.
ER and organellar Ca2+ dynamics
In simple terms: The endoplasmic reticulum stores and releases calcium, helping maintain cytosolic calcium levels.
The endoplasmic reticulum (ER) maintains ion homeostasis required for plasma membrane repair, and its Ca2+ handling is coupled to cytosolic Ca2+ signals. In plants, calcium and manganese transport across organellar compartments is similarly integrated, showing that organellar Ca2+ dynamics are conserved themes in cell physiology. These organellar fluxes contribute to the overall process of calcium ion import into cytosol by supplying or buffering cytosolic Ca2+.
Lysosomal Ca2+ import and ion homeostasis
In simple terms: Lysosomes use transporters to move calcium and control their internal ion balance.
Lysosomal TMEM165 controls cellular ion homeostasis and survival by mediating lysosomal Ca2+ import and H+ efflux. This illustrates that calcium ion import into cytosol is not limited to the plasma membrane and mitochondria but also involves endolysosomal compartments. Lysosomal Ca2+ handling is therefore a distinct contributor to cytosolic Ca2+ regulation and cell survival.
Feedback regulation and signaling hubs
In simple terms: Cells use kinases and microRNAs to adjust how much calcium enters the cytosol.
Calcium import is regulated by signaling molecules. In Saccharomyces cerevisiae, calmodulin kinase 2 (Cmkl2) genetically interacts with Rch1p to negatively regulate calcium import after an extracellular calcium pulse. In Huntington's disease, miR-34a-5p acts as a molecular hub of pathomechanisms, linking Ca2+ signaling to neurodegeneration. These examples show that calcium ion import into cytosol is embedded in kinase and microRNA regulatory networks.
Key Genes Involved in GO:1902656 calcium ion import into cytosol
The following genes and proteins are experimentally linked to calcium ion import into cytosol or to the ion homeostasis pathways that control it.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TMEM165 | Mediates lysosomal Ca2+ import and H+ efflux; controls ion homeostasis and survival | Loss-of-function studies in lysosomal ion balance and cell survival |
| MCU | Core channel of the mitochondrial calcium uniporter complex | Mitochondrial Ca2+ uptake and metabolism studies |
| MICU1 | Regulatory subunit of the MCU complex | Gatekeeping of mitochondrial Ca2+ uptake |
| MICU2 | Regulatory subunit of the MCU complex | Fine-tuning of mitochondrial Ca2+ import |
| EMRE | Essential MCU regulator in the mitochondrial calcium uniporter complex | Assembly and function of mitochondrial Ca2+ uptake |
| CMK2 (Cmkl2) | Calmodulin kinase 2; negatively regulates calcium import in yeast | Yeast calcium pulse and genetic interaction studies |
| RCH1 | Yeast regulator genetically interacting with Cmkl2 in calcium import | Negative regulation of calcium import after extracellular calcium pulse |
| MIR34A | miR-34a-5p; molecular hub of pathomechanisms in Huntington's disease | miRNA-based regulation of Ca2+ signaling in neurodegeneration |
| SEC61A1 | Sec61 complex subunit; mutations cause Sec61-channelopathies affecting ion homeostasis | Disease modeling of protein translocation and ion balance |
| ATP2B1 (PMCA1) | Plasma membrane Ca2+ ATPase; exports Ca2+ to balance import | Calcium export and cytosolic Ca2+ homeostasis studies |
| ATP2B2 (PMCA2) | Plasma membrane Ca2+ ATPase isoform | Calcium export and signaling studies |
| ATP2B3 (PMCA3) | Plasma membrane Ca2+ ATPase isoform | Calcium export and neuronal Ca2+ handling |
| ATP2B4 (PMCA4) | Plasma membrane Ca2+ ATPase isoform | Calcium export and cell survival studies |
| SLC8A1 (NCX1) | Na+/Ca2+ exchanger; contributes to Ca2+ efflux and homeostasis | Calcium export and cytosolic Ca2+ regulation |
| SLC8A2 (NCX2) | Na+/Ca2+ exchanger isoform | Neuronal calcium homeostasis studies |
| SLC8A3 (NCX3) | Na+/Ca2+ exchanger isoform | Calcium export and signaling studies |
| CALM1 | Calmodulin; Ca2+ sensor that modulates import and export pathways | Calcium signaling and kinase regulation studies |
| MICU3 | MCU complex regulator in excitable tissues | Tissue-specific mitochondrial Ca2+ uptake studies |
How Is calcium ion import into cytosol Regulated?
Calcium ion import into cytosol is regulated at multiple levels. In yeast, calmodulin kinase 2 (Cmkl2) genetically interacts with Rch1p to negatively regulate calcium import after an extracellular calcium pulse, providing a feedback mechanism that prevents excessive cytosolic Ca2+. In mammalian cells, mitochondrial Ca2+ uptake through the MCU complex is controlled by regulatory subunits such as MICU1, MICU2, and MICU3, which gate channel activity according to cytosolic Ca2+ levels. Lysosomal TMEM165 controls ion homeostasis and survival by mediating lysosomal Ca2+ import and H+ efflux, linking Ca2+ import to organellar pH regulation. The ER maintains ion homeostasis required for plasma membrane repair, coupling Ca2+ handling to membrane integrity. In Huntington's disease, miR-34a-5p acts as a molecular hub that coordinates pathomechanisms, including Ca2+ signaling. Together, these mechanisms ensure that calcium ion import into cytosol is tuned to cellular demand and stress.
calcium ion import into cytosol and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MIR34A | Huntington's disease; miR-34a-5p as molecular hub of pathomechanisms | Neuronal cell models with miR-34a-5p knockout or overexpression |
| TMEM165 | Lysosomal ion homeostasis and cell survival defects | TMEM165 knockout cells for lysosomal Ca2+ import assays |
| SEC61A1 | Sec61-channelopathies affecting protein translocation and ion homeostasis | Patient-derived cells or Sec61A1 mutant knock-in models |
| MCU | Mitochondrial Ca2+ overload and cell death | MCU knockout or point-mutation cells for mitochondrial Ca2+ uptake |
| ATP2B1 | Calcium export imbalance and cytosolic Ca2+ overload | ATP2B1 knockout cells for Ca2+ homeostasis studies |
Huntington's disease and Ca2+ signaling
Sec61-channelopathies and ion homeostasis
Lysosomal dysfunction and cell survival
ER stress and membrane repair defects
From calcium ion import into cytosol-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does a candidate gene regulate cytosolic Ca2+ import? | |
| Does a specific point mutation alter channel or transporter activity? | |
| Does tagging a transporter affect its localization and function? | |
| Does overexpression of a regulator increase Ca2+ import? | |
| Which genes are required for lysosomal Ca2+ import? | |
| How does a disease-linked variant affect ion homeostasis? |
How to Study the calcium ion import into cytosol Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live-cell Ca2+ imaging | Real-time cytosolic Ca2+ concentration changes | Measuring calcium ion import into cytosol after stimulation |
| Organelle-targeted Ca2+ probes | Ca2+ dynamics in mitochondria, ER, or lysosomes | Dissecting compartment-specific import steps |
| CRISPR knockout screening | Genes required for Ca2+ import | Identifying regulators of cytosolic Ca2+ entry |
| Genetic interaction assays | Epistatic relationships between regulators | Mapping Cmkl2-Rch1p interactions in yeast |
| RNA sequencing | Transcriptional changes in Ca2+ transport genes | Linking import pathways to disease states |
| miRNA profiling | Expression of regulatory microRNAs | Identifying miR-34a-5p targets in neurodegeneration |
| Ion homeostasis assays | Lysosomal and cellular ion balance | Evaluating TMEM165 function and survival |
| Membrane repair assays | Cell membrane integrity after damage | Testing ER ion homeostasis requirements |
Live-cell Ca2+ imaging
Organelle-specific Ca2+ probes
Genetic interaction and knockout studies
Transcriptomics and miRNA profiling
How CRISPR Can Be Used to Study GO:1902656 calcium ion import into cytosol
Knockout
Point Mutation
Knock-in
Overexpression
How EDITGENE Supports calcium ion import into cytosol Research
Researchers studying calcium ion import into cytosol-related genes often need to determine whether a candidate gene is causally involved in Ca2+ transport, ion homeostasis, or disease-associated signaling. EDITGENE provides CRISPR-based cell model services that enable loss-of-function, gain-of-function, and precise variant modeling for these studies.
Contact EDITGENE today to design your custom CRISPR model for calcium ion import into cytosol research.
Frequently Asked Questions About calcium ion import into cytosol
What is calcium ion import into cytosol (GO:1902656)?
It is the biological process defined as the directed movement of calcium ion into a cytosol, covering Ca2+ entry from outside the cell or from organelle stores into the cytosol.
What genes are involved in calcium ion import into cytosol?
Key genes include TMEM165 for lysosomal Ca2+ import, MCU and its regulators for mitochondrial uptake, Cmkl2 and Rch1p in yeast, and miR-34a-5p in Huntington's disease.
How is calcium ion import into cytosol regulated?
It is regulated by kinases such as calmodulin kinase 2, by MCU complex subunits like MICU1 and MICU2, and by microRNAs such as miR-34a-5p.
Which organelles are involved in calcium ion import into cytosol?
The plasma membrane, mitochondria, endoplasmic reticulum, and lysosomes all contribute to Ca2+ movement into the cytosol.
Why is calcium ion import into cytosol important for cells?
Cytosolic Ca2+ controls secretion, contraction, gene expression, metabolism, and survival, so import must be tightly regulated.
What diseases are linked to calcium ion import into cytosol?
Huntington's disease, Sec61-channelopathies, lysosomal dysfunction, and ER stress-related membrane repair defects have been linked to altered Ca2+ handling.
How do researchers measure calcium ion import into cytosol?
Live-cell Ca2+ imaging with fluorescent indicators and organelle-targeted probes are standard methods.
Can CRISPR be used to study calcium ion import into cytosol?
Yes, CRISPR knockout, point-mutation, knock-in, and overexpression models are used to test gene function in Ca2+ import.
What is the role of TMEM165 in calcium import?
TMEM165 mediates lysosomal Ca2+ import and H+ efflux, controlling cellular ion homeostasis and survival.
What is the role of the MCU complex in calcium import?
The MCU complex mediates mitochondrial Ca2+ uptake driven by the mitochondrial membrane potential, shaping cytosolic Ca2+ signals.
Conclusion
Calcium ion import into cytosol (GO:1902656) is a central biological process that delivers Ca2+ to the cytosol for signaling, metabolism, and survival. It involves coordinated transport at the plasma membrane, mitochondria, ER, and lysosomes, with regulation by kinases, channel subunits, and microRNAs. Dysregulation of these pathways is linked to Huntington's disease, Sec61-channelopathies, lysosomal dysfunction, and membrane repair defects. CRISPR-based cell models provide a powerful approach to dissect the genes and mechanisms controlling this process.
References
- 1. Chen R et al.. 2025. Lysosomal TMEM165 controls cellular ion homeostasis and survival by mediating lysosomal Ca(2+) import and H(+) efflux.. Nat Commun 16(1):5209 PMID: 40473625
- 2. Santo-Domingo J et al.. 2010. Calcium uptake mechanisms of mitochondria.. Biochim Biophys Acta 1797(6-7):907-12 PMID: 20079335
- 3. Guerini D et al.. 2005. Exporting calcium from cells.. Cell Calcium 38(3-4):281-9 PMID: 16102821
- 4. Chandra G et al.. 2021. Endoplasmic reticulum maintains ion homeostasis required for plasma membrane repair.. J Cell Biol 220(5) PMID: 33688936
- 5. Coleman CE et al.. 2022. Calmodulin kinase 2 genetically interacts with Rch1p to negatively regulate calcium import into Saccharomyces cerevisiae after extracellular calcium pulse.. Arch Microbiol 204(8):519 PMID: 35871646
- 6. He J et al.. 2021. Transport, functions, and interaction of calcium and manganese in plant organellar compartments.. Plant Physiol 187(4):1940-1972 PMID: 35235665
- 7. Sicking M et al.. 2021. Complexity and Specificity of Sec61-Channelopathies: Human Diseases Affecting Gating of the Sec61 Complex.. Cells 10(5) PMID: 33925740
- 8. Hart M et al.. 2023. miR-34a-5p as molecular hub of pathomechanisms in Huntington's disease.. Mol Med 29(1):43 PMID: 37013480
