terminal cisterna
Definition
Target type: cellularcomponent
The portion of sarcoplasmic reticulum devoted to calcium ion storage and calcium ion release. [GOC:mtg_muscle]
The terminal cisterna is a specialized region of the sarcoplasmic reticulum (SR), a network of membrane-bound compartments within muscle cells. It is characterized by its close proximity to the transverse tubules (T-tubules), invaginations of the plasma membrane that extend deep into the muscle fiber. Terminal cisternae are flattened, sac-like structures that lie on either side of a T-tubule, forming a triad (two terminal cisternae flanking a T-tubule). This close association is crucial for the excitation-contraction coupling process, where an electrical signal traveling along the T-tubule triggers the release of calcium from the SR.
The terminal cisterna is enriched in calcium channels called ryanodine receptors (RyRs), which are responsible for releasing calcium into the cytosol. These channels are activated by a conformational change in the dihydropyridine receptors (DHPRs) located within the T-tubule membrane. When the DHPRs sense a depolarization wave, they undergo a change in shape that triggers the opening of the RyRs, allowing calcium to flow from the terminal cisterna into the muscle cell.
The terminal cisterna also contains a high concentration of calcium-binding proteins, such as calsequestrin, which help to buffer the concentration of calcium within the SR. This buffering mechanism is important for ensuring that the calcium released from the SR can be quickly reabsorbed, allowing for the relaxation of the muscle fiber after contraction.
In summary, the terminal cisterna is a specialized region of the SR that plays a critical role in muscle contraction. Its close association with the T-tubule and its high concentration of calcium channels and binding proteins enable the rapid release and uptake of calcium, facilitating the excitation-contraction coupling process.'
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Proteins (2)
| Protein | Definition | Taxonomy |
|---|---|---|
| Peptidyl-prolyl cis-trans isomerase FKBP1A | A peptidyl-prolyl cis-trans isomerase FKBP1A that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62942] | Homo sapiens (human) |
| Ryanodine receptor 1 | A ryanodine receptor 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P21817] | Homo sapiens (human) |
Compounds (13)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| nevirapine | nevirapine : A dipyridodiazepine that is 5,11-dihydro-6H-dipyrido[3,2-b:2',3'-e][1,4]diazepine which is substituted by methyl, oxo, and cyclopropyl groups at positions 4, 6, and 11, respectively. A non-nucleoside reverse transcriptase inhibitor with activity against HIV-1, it is used in combination with other antiretrovirals for the treatment of HIV infection. Nevirapine: A potent, non-nucleoside reverse transcriptase inhibitor used in combination with nucleoside analogues for treatment of HIV INFECTIONS and AIDS. | cyclopropanes; dipyridodiazepine | antiviral drug; HIV-1 reverse transcriptase inhibitor |
| thiabendazole | Tresaderm: dermatologic soln containing dexamethasone, thiabendazole & neomycin sulfate | 1,3-thiazoles; benzimidazole fungicide; benzimidazoles | antifungal agrochemical; antinematodal drug |
| cycloheximide | cycloheximide : A dicarboximide that is 4-(2-hydroxyethyl)piperidine-2,6-dione in which one of the hydrogens attached to the carbon bearing the hydroxy group is replaced by a 3,5-dimethyl-2-oxocyclohexyl group. It is an antibiotic produced by the bacterium Streptomyces griseus. Cycloheximide: Antibiotic substance isolated from streptomycin-producing strains of Streptomyces griseus. It acts by inhibiting elongation during protein synthesis. | antibiotic fungicide; cyclic ketone; dicarboximide; piperidine antibiotic; piperidones; secondary alcohol | anticoronaviral agent; bacterial metabolite; ferroptosis inhibitor; neuroprotective agent; protein synthesis inhibitor |
| 3-(3-pyridyl)-1-propyl-(2s)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarboxylate | |||
| tacrolimus | tacrolimus (anhydrous) : A macrolide lactam containing a 23-membered lactone ring, originally isolated from the fermentation broth of a Japanese soil sample that contained the bacteria Streptomyces tsukubaensis. Tacrolimus: A macrolide isolated from the culture broth of a strain of Streptomyces tsukubaensis that has strong immunosuppressive activity in vivo and prevents the activation of T-lymphocytes in response to antigenic or mitogenic stimulation in vitro. | macrolide lactam | bacterial metabolite; immunosuppressive agent |
| N-(2-fluorophenyl)-2-[2-(4-thiazolyl)-1-benzimidazolyl]acetamide | benzimidazoles | ||
| biricodar | biricodar: a non-macrocyclic ligand for FKBP12; structure in first source | alpha-amino acid ester | |
| l 683590 | immunomycin: from Streptomyces hygroscopicus; structure given in first source | ether; lactol; macrolide; secondary alcohol | antifungal agent; bacterial metabolite; immunosuppressive agent |
| cyclosporine | ramihyphin A: one of the metabolites produced by Fusarium sp. S-435; RN given refers to cpd with unknown MF | homodetic cyclic peptide | anti-asthmatic drug; anticoronaviral agent; antifungal agent; antirheumatic drug; carcinogenic agent; dermatologic drug; EC 3.1.3.16 (phosphoprotein phosphatase) inhibitor; geroprotector; immunosuppressive agent; metabolite |
| sirolimus | sirolimus : A macrolide lactam isolated from Streptomyces hygroscopicus consisting of a 29-membered ring containing 4 trans double bonds, three of which are conjugated. It is an antibiotic, immunosupressive and antineoplastic agent. Sirolimus: A macrolide compound obtained from Streptomyces hygroscopicus that acts by selectively blocking the transcriptional activation of cytokines thereby inhibiting cytokine production. It is bioactive only when bound to IMMUNOPHILINS. Sirolimus is a potent immunosuppressant and possesses both antifungal and antineoplastic properties. | antibiotic antifungal drug; cyclic acetal; cyclic ketone; ether; macrolide lactam; organic heterotricyclic compound; secondary alcohol | antibacterial drug; anticoronaviral agent; antineoplastic agent; bacterial metabolite; geroprotector; immunosuppressive agent; mTOR inhibitor |
| bastadin 5 | |||
| timcodar | timcodar: a mutlidrug resistance inhibitor; structure in first source | ||
| bastadin 4 |