Page last updated: 2024-10-24

sequestering of calcium ion

Definition

Target type: biologicalprocess

The process of binding or confining calcium ions such that they are separated from other components of a biological system. [GOC:ai]

Calcium sequestration is a crucial biological process that involves the removal and storage of calcium ions (Ca2+) from the cytosol, the fluid inside cells. This process is essential for maintaining cellular homeostasis and regulating various cellular functions, including muscle contraction, neurotransmission, and cell signaling.

**Mechanisms of Calcium Sequestration:**

1. **Active Transport:** Calcium pumps, specifically calcium ATPases, use energy derived from ATP hydrolysis to actively transport Ca2+ ions across cellular membranes against their concentration gradient. This process results in the accumulation of Ca2+ in intracellular compartments, like the sarcoplasmic reticulum (SR) in muscle cells or the endoplasmic reticulum (ER) in other cells.

2. **Calcium Binding Proteins:** Proteins like calmodulin, troponin C, and parvalbumin have a high affinity for Ca2+ ions. They bind to Ca2+ and sequester it within the cytosol, effectively reducing the free Ca2+ concentration.

**Key Locations for Calcium Sequestration:**

- **Sarcoplasmic Reticulum (SR) in Muscle Cells:** The SR is a specialized organelle that stores large amounts of Ca2+. During muscle contraction, Ca2+ is released from the SR into the cytosol, triggering the interaction of actin and myosin filaments. After contraction, the Ca2+ is actively pumped back into the SR, allowing the muscle to relax.

- **Endoplasmic Reticulum (ER):** The ER serves as a major calcium storage site in most cells. Calcium pumps in the ER membrane actively transport Ca2+ from the cytosol into the ER lumen, where it is stored bound to proteins.

- **Mitochondria:** Mitochondria also play a role in Ca2+ sequestration, although their capacity is typically lower than that of the SR or ER. They can buffer cytosolic Ca2+ levels, but their primary function is in energy production through oxidative phosphorylation.

**Regulation of Calcium Sequestration:**

- **Hormones and Neurotransmitters:** Hormones like epinephrine and neurotransmitters like acetylcholine can trigger the release of Ca2+ from intracellular stores, initiating various cellular responses.

- **Intracellular Signaling Pathways:** Changes in cellular conditions, such as pH or phosphorylation, can affect the activity of calcium pumps and other proteins involved in Ca2+ sequestration.

**Consequences of Calcium Sequestration Dysregulation:**

- **Muscle Weakness and Fatigue:** Inadequate Ca2+ sequestration in muscle cells can lead to impaired muscle function and fatigue.

- **Neurological Disorders:** Dysregulation of Ca2+ homeostasis in neurons can contribute to conditions like epilepsy, Alzheimer's disease, and Parkinson's disease.

- **Cardiac Arrhythmias:** Abnormal Ca2+ handling in heart muscle cells can disrupt heart rhythm and lead to arrhythmias.

In summary, calcium sequestration is a vital process that plays a critical role in maintaining cellular function and regulating diverse physiological processes. Its precise regulation is crucial for normal cellular activity, and any disruption in this process can have significant consequences for health.'
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Proteins (2)

ProteinDefinitionTaxonomy
Presenilin-1A presenilin-1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P49768]Homo sapiens (human)
EndoplasminAn endoplasmin that is encoded in the genome of human. [PRO:DAN]Homo sapiens (human)

Compounds (44)

CompoundDefinitionClassesRoles
tocopheroxy radicaltocopheroxy radical: RN given refers to radical ion (1+), (2R-(2R*(4R*,8R*)))-isomer; RN for cpd without isomeric designation not available 12/90tocopherol
7-amino-4-chloro-3-methoxy-2-benzopyran-1-oneisocoumarins
adenosine diphosphateAdenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.adenosine 5'-phosphate;
purine ribonucleoside 5'-diphosphate
fundamental metabolite;
human metabolite
2-chloroadenosine5-chloroformycin A: structure given in first sourcepurine nucleoside
adenosinequinquefolan B: isolated from roots of Panax quinquefolium L.; RN not in Chemline 10/87; RN from Toxlitadenosines;
purines D-ribonucleoside
analgesic;
anti-arrhythmia drug;
fundamental metabolite;
human metabolite;
vasodilator agent
tarenflurbiltarenflurbil: R-enantiomer of flurbiprofen but not a COX inhibitor; modulates NF-kB, gamma-secretase, amyloid beta-protein;flurbiprofen
cholanic acid5beta-cholanic acids;
cholanic acid
adenosine-5'-carboxylic acidpurine nucleoside
adenosine 5'-carboxamideadenosine 5'-carboxamide: structure
5'-n-methylcarboxamideadenosine5'-N-methylcarboxamideadenosine: RN given refers to (beta-D)-isomer
n-methyladenosineN-methyladenosine: is a inhibitor of cell differentiation

N(6)-methyladenosine : A methyladenosine compound with one methyl group attached to N(6) of the adenine nucleobase.
methyladenosine
ethyl adenosine-5'-carboxylateethyl adenosine-5'-carboxylate: potent vasoactive substance; RN given refers to parent cpd
adenosine 5'-phosphoramidateadenosine 5'-phosphoramidate : The phosphoramadite analogue of AMP.organic phosphoramidateMycoplasma genitalium metabolite
t0901317T0901317: an LXRalpha and LXRbeta agonist
adenosine-5'-(n-ethylcarboxamide)Adenosine-5'-(N-ethylcarboxamide): A stable adenosine A1 and A2 receptor agonist. Experimentally, it inhibits cAMP and cGMP phosphodiesterase activity.

N-ethyl-5'-carboxamidoadenosine : A derivative of adenosine in which the 5'-hydroxymethyl group is replaced by an N-ethylcarboxamido group.
adenosines;
monocarboxylic acid amide
adenosine A1 receptor agonist;
adenosine A2A receptor agonist;
antineoplastic agent;
EC 3.1.4.* (phosphoric diester hydrolase) inhibitor;
vasodilator agent
adenosine-5'-(N-propyl)carboxamideadenosine-5'-(N-propyl)carboxamide : A monocarboxylic acid amide that is the propyl amide of adenosine 5'-carboxylic acid.adenosines;
monocarboxylic acid amide
n-(n-(3,5-difluorophenacetyl)alanyl)phenylglycine tert-butyl esterDAPT : A dipeptide consisting of alanylphenylglycine derivatised as a 3,5-difluorophenylacetamide at the amino terminal and a tert-butyl ester at the carboxy terminal. A gamma-secretase inhibitor.carboxylic ester;
difluorobenzene;
dipeptide;
tert-butyl ester
EC 3.4.23.46 (memapsin 2) inhibitor
sulindac sulfidesulindac sulfide : An aryl sulfide that is a metabolite of sulindac. A non-steroidal anti-inflammatory drug, which also has anticancer activity.

sulindac sulfide: sulfated analog of indomethacin & inhibitor of prostaglandin synthesis in vitro; RN given refers to cpd without isomeric designation; structure given in first source
aryl sulfide;
monocarboxylic acid;
organofluorine compound
antineoplastic agent;
apoptosis inducer;
non-steroidal anti-inflammatory drug
l 685458L 685458: a gamma-secretase inhibitor; structure in first source

L-685,458 : A peptide and carboxamide that is L-leucyl-L-phenylalaninamide, L-Leu-L-Phe-NH2, which has been acylated on the N-terminus by a Phe-Phe hydroxyethylene dipeptide isotere, 2R-benzyl-5S-tert-butoxycarbonylamino-4R-hydroxy-6-phenylhexanoic acid. Compounds based on the structure of L-685,458 are potent inhibitors of gamma-secretase, which mediates the final catalytic step that generates the amyloid beta-peptide (Abeta), which assembles into the neurotoxic aggregates in the brains of sufferers of Alzheimer's disease.
carbamate ester;
monocarboxylic acid amide;
peptide;
secondary alcohol
EC 3.4.23.46 (memapsin 2) inhibitor;
peptidomimetic
1-aminoadenosine1-aminoadenosine: structure
9h-purine-9-propanamine, 6-amino-8-((6-iodo-1,3-benzodioxol-5-yl)thio)-n-(1-methylethyl)-9H-purine-9-propanamine, 6-amino-8-((6-iodo-1,3-benzodioxol-5-yl)thio)-N-(1-methylethyl)-: an epichaperome (purine-scaffold) inhibitor; structure in first source
mk 0752
5'-amino-5'-deoxyadenosine
ly 450139peptide
chf 50741-(3',4'-dichloro-2-fluoro(1,1'-biphenyl)-4-yl)cyclopropanecarboxylic acid: a beta-amyloid(1-42) lowering agent; structure in first source
n-cyclopropyl adenosine-5'-carboxamide
ly 411575dibenzoazepine;
difluorobenzene;
lactam;
secondary alcohol
EC 3.4.23.46 (memapsin 2) inhibitor
4-(2-((1r)-1-(((4-chlorophenyl)sulfonyl)-2,5-difluoroanilino)ethyl)-5-fluorophenyl)butanoic acidsulfonamide
begacestat
ec 144EC 144: structure in first source
e 2012
mrk 560MRK 560: a gamma-secretase inhibitor; MRK-560 is the (cis)-isomer; structure in first source
at 13387(2,4-dihydroxy-5-isopropylphenyl)-(5-(4-methylpiperazin-1-ylmethyl)-1,3-dihydroisoindol-2-yl)methanone: structure in first source

onalespib : A member of the class of isoindoles that is isoindole in which the amino group has been acylated by a 2,4-dihydroxy-5-isopropylbenzoyl group and in which position 5 of the isoidole moiety has been substituted by a (4-methylpiperazin-1-yl)methyl group. A second-generation Hsp90 inhibitor.
benzamides;
isoindoles;
N-alkylpiperazine;
resorcinols;
tertiary carboxamide
antineoplastic agent;
Hsp90 inhibitor
cnf 20242-aminopurines;
aromatic ether;
organochlorine compound;
pyridines
antineoplastic agent;
Hsp90 inhibitor
snx 2112SNX 2112: an orally available small molecule Hsp90 inhibitor; structure in first source
1, 3-di-(n-carboxybenzoyl-leucyl-leucyl)amino acetone1, 3-di-(N-carboxybenzoyl-leucyl-leucyl)amino acetone: structure in first source
pf 3084014nirogacestat : A member of the class of imidazoles that is 1H-imidazole substituted by a 1-[(2,2-dimethylpropyl)amino]-2-methylpropan-2-yl group at position 1 and a {N-[(2S)-6,8-difluoro-1,2,3,4-tetrahydronaphthalen-2-yl]-L-norvalyl}amino group at position 4. It is a gamma-secretase inhibitor whose hydrobromide salt is indicated for adult patients with progressing desmoid tumours who require systemic treatment.

nirogacestat: an antineoplastic agent
bms 708163BMS 708163: structure in first sourceoxadiazole;
ring assembly
ro 4929097dibenzoazepine;
dicarboxylic acid diamide;
lactam;
organofluorine compound
EC 3.4.23.46 (memapsin 2) inhibitor
jnj 40418677
(r)-4-cyclopropyl-7,8-difluoro-5-(4-(trifluoromethyl)phenylsulfonyl)-4,5-dihydro-1h-pyrazolo(4,3-c)quinoline(R)-4-cyclopropyl-7,8-difluoro-5-(4-(trifluoromethyl)phenylsulfonyl)-4,5-dihydro-1H-pyrazolo(4,3-c)quinoline: gamma secretase inhibitor; structure in first source
tas-116
ver 52296luminespib : A monocarboxylic acid amide obtained by formal condensation of the carboxy group of 5-(2,4-dihydroxy-5-isopropylphenyl)-4-[4-(morpholin-4-ylmethyl)phenyl]-1,2-oxazole-3-carboxylic acid with the amino group of ethylamine.aromatic amide;
isoxazoles;
monocarboxylic acid amide;
morpholines;
resorcinols
angiogenesis inhibitor;
antineoplastic agent;
Hsp90 inhibitor
sta 9090ring assembly;
triazoles