Target type: cellularcomponent
Fibers, composed of actin, myosin, and associated proteins, found in cells of smooth or striated muscle. [GOC:go_curators, ISBN:0815316194]
Contractile muscle fibers, also known as myofibers, are highly specialized elongated cells responsible for muscle contraction. They are composed of multiple cellular components that work together to generate force and movement. These components can be broadly categorized into three main levels:
1. **Myofibrils:** These are the fundamental units of muscle contraction, composed of repeating units called sarcomeres. Sarcomeres are the basic functional unit of a muscle fiber and consist of two primary protein filaments:
* **Actin filaments:** Thin filaments that are composed of the protein actin. They are anchored to the Z-discs, which are structural proteins that define the boundaries of a sarcomere.
* **Myosin filaments:** Thick filaments that are composed of the protein myosin. They are responsible for generating the force needed for muscle contraction.
2. **Sarcolemma:** This is the plasma membrane of a muscle fiber. It surrounds the myofibrils and plays a crucial role in transmitting nerve impulses to initiate muscle contraction. The sarcolemma is also involved in regulating the passage of ions and nutrients into and out of the muscle fiber.
3. **Sarcoplasmic reticulum:** This is a specialized network of intracellular membranes that surrounds each myofibril. It is responsible for storing and releasing calcium ions, which are essential for muscle contraction. The sarcoplasmic reticulum contains specialized structures called terminal cisternae, which are located near the T-tubules (transverse tubules).
**T-tubules:** These are invaginations of the sarcolemma that extend deep into the muscle fiber. They play a vital role in transmitting the nerve impulse from the sarcolemma to the sarcoplasmic reticulum, triggering the release of calcium ions and initiating muscle contraction.
These components work in a coordinated manner to generate force and movement. Upon receiving a nerve impulse, the sarcolemma depolarizes, which triggers the release of calcium ions from the sarcoplasmic reticulum. Calcium ions bind to troponin, a protein associated with the actin filaments. This binding causes a conformational change in troponin, which in turn moves tropomyosin, another protein associated with actin, out of the way. This exposes the myosin-binding sites on actin, allowing myosin to bind and initiate the sliding filament mechanism, leading to muscle contraction.
In summary, the cellular components of a contractile muscle fiber include myofibrils, sarcolemma, sarcoplasmic reticulum, T-tubules, and the various proteins that compose these structures. Each component plays a specific role in ensuring the proper function of the muscle fiber, allowing for the generation of force and movement.'
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Protein | Definition | Taxonomy |
---|---|---|
Cyclin-dependent kinase 5 activator 1 | A cyclin-dependent kinase 5 activator 1 that is encoded in the genome of human. [PRO:DNx] | Homo sapiens (human) |
Gap junction alpha-1 protein | A gap junction alpha-1 protein that is encoded in the genome of human. [PRO:DNx, UniProtKB:P17302] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
tacrine | tacrine : A member of the class of acridines that is 1,2,3,4-tetrahydroacridine substituted by an amino group at position 9. It is used in the treatment of Alzheimer's disease. Tacrine: A cholinesterase inhibitor that crosses the blood-brain barrier. Tacrine has been used to counter the effects of muscle relaxants, as a respiratory stimulant, and in the treatment of Alzheimer's disease and other central nervous system disorders. | acridines; aromatic amine | EC 3.1.1.7 (acetylcholinesterase) inhibitor |
gw8510 | GW8510: 3' substituted indolone as a scaffold for the development of neuroprotective drug; structure in first source | ||
indirubin-3'-monoxime | indirubin-3'-monoxime : A member of the class of biindoles that is indirubin in which the keto group at position 3' has undergone condensation with hydroxylamine to form the corresponding oxime. indirubin-3'-monoxime: has antiangiogenic activity | ||
indirubin-5-sulfonate | |||
nsc 664704 | kenpaullone : An indolobenzazepine that is paullone in which the hydrogen at position 9 is replaced by a bromo substituent. It is an ATP-competitive inhibitor of cyclin-dependent kinases (CDKs) and glycogen synthase kinase 3beta (GSK3beta). kenpaullone: inhibits CDK1/cyclin B; structure in first source | indolobenzazepine; lactam; organobromine compound | cardioprotective agent; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor; EC 2.7.11.26 (tau-protein kinase) inhibitor; geroprotector |
nu6102 | NU6102: structure in first source | ||
olomoucine | olomoucine : A 9H-purine that is substituted by a (2-hydroxyethyl)nitrilo, benzylnitrilo and a methyl group at positions 2,6 and 9, respectively. It is a cyclin-dependent kinase inhibitor. olomoucine: inhibits protein P34CDC2 | 2,6-diaminopurines; ethanolamines | EC 2.7.11.22 (cyclin-dependent kinase) inhibitor |
kanamycin a | kanamycin : Kanamycin is a naturally occurring antibiotic complex from Streptomyces kanamyceticus that consists of several components: kanamycin A, the major component (also usually designated as kanamycin), and kanamycins B, C, D and X the minor components. Kanamycin: Antibiotic complex produced by Streptomyces kanamyceticus from Japanese soil. Comprises 3 components: kanamycin A, the major component, and kanamycins B and C, the minor components. | kanamycins | bacterial metabolite |
indirubin | |||
indigo | hydroxyindoles | ||
2-phenylindole | alpha-phenylindole: RN given refers to parent cpd | phenylindole | |
staurosporine | indolocarbazole alkaloid; organic heterooctacyclic compound | apoptosis inducer; bacterial metabolite; EC 2.7.11.13 (protein kinase C) inhibitor; geroprotector | |
cercosporamide | cercosporamide : A member of the class of dibenzofurans that is a potent broad spectrum antifungal agent isolated from the fungus Cercosporidium henningsii. cercosporamide: antineoplastic; RN refers to (S)-isomer | dibenzofurans; methyl ketone; monocarboxylic acid amide; polyphenol | antifungal agent; EC 2.7.11.24 (mitogen-activated protein kinase) inhibitor; fungal metabolite; phytotoxin |
birb 796 | aromatic ether; morpholines; naphthalenes; pyrazoles; ureas | EC 2.7.11.24 (mitogen-activated protein kinase) inhibitor; immunomodulator | |
cyc 202 | seliciclib : 2,6-Diaminopurine carrying benzylamino, (2R)-1-hydroxybutan-2-yl and isopropyl substituents at C-6, C-2-N and N-9 respectively. It is an experimental drug candidate in the family of pharmacological cyclin-dependent kinase (CDK) inhibitors. | 2,6-diaminopurines | antiviral drug; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor |
paullone | paullone : An indolobenzazepine that is 5,6,7,12-tetrahydroindolo[3,2-d][1]benzazepine carrying an oxo substituent at position 6. paullone: structure in first source | indolobenzazepine; lactam | EC 2.7.11.22 (cyclin-dependent kinase) inhibitor; EC 2.7.11.26 (tau-protein kinase) inhibitor |
meridianin g | meridianin G: from the tunicate Aplidium meridianum; structure in first source | ||
5-iodoindirubin-3'-monoxime | 5-iodoindirubin-3'-monoxime: inhibits GSK-3beta | ||
2H-pyrazolo[4,3-b]quinoxalin-3-amine | quinoxaline derivative | ||
n-(4-methoxybenzyl)-n'-(5-nitro-1,3-thiazol-2-yl)urea | N-(4-methoxybenzyl)-N'-(5-nitro-1,3-thiazol-2-yl)urea: structure in first source | ||
7-n-butyl-6-(4'-hydroxyphenyl)-5h-pyrrolo(2,3b)pyrazine | |||
6-bromoindirubin-3'-oxime | 6-bromoindirubin-3'-oxime : A member of the class of biindoles that is indirubin substituted at position 6 by a bromo group and in which the keto group at position 3' has undergone condensation with hydroxylamine to form the corresponding oxime. 6-bromoindirubin-3'-oxime: structure in first source | ||
purvalanol b | purvalanol B: protein kinase inhibitor; structure in first source | purvalanol | protein kinase inhibitor |
purvalanol a | 6-((3-chloro)anilino)-2-(isopropyl-2-hydroxyethylamino)-9-isopropylpurine: purvalanol A is the (1R)-isomer; | purvalanol | |
2-methyl-5-(4-methylanilino)-1,3-benzothiazole-4,7-dione | aminotoluene | ||
cgp 60474 | substituted aniline | ||
cgp 74514a | |||
1,4-dimethoxy-10H-acridine-9-thione | acridines | ||
bms 387032 | N-(5-(((5-(1,1-dimethylethyl)-2-oxazolyl)methyl)thio)-2-thiazolyl)-4-piperidinecarboxamide: a CDK2 inhibitor with antineoplastic activity; structure in first source N-(5-{[(5-tert-butyl-1,3-oxazol-2-yl)methyl]sulfanyl}-1,3-thiazol-2-yl)piperidine-4-carboxamide : A secondary carboxamide resulting from the formal condensation of the carboxy group of piperidine-4-carboxylic acid with the amino group of 5-{[(5-tert-butyl-1,3-oxazol-2-yl)methyl]sulfanyl}-1,3-thiazol-2-amine. It is an ATP-competitive inhibitor of CDK2, CDK7 and CDK9 kinases and exhibits anti-cancer properties. | 1,3-oxazoles; 1,3-thiazoles; organic sulfide; piperidinecarboxamide; secondary carboxamide | angiogenesis inhibitor; antineoplastic agent; apoptosis inducer; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor |
7-butyl-6-(4-methoxyphenyl)-5H-pyrrolo[2,3-b]pyrazine | pyrroles | ||
alsterpaullone | alsterpaullone : An organic heterotetracyclic compound that is 1,3-dihydro-2H-1-benzazepin-2-one which shares its 4-5 bond with the 3-2 bond of 5-nitro-1H-indole. alsterpaullone: structure in first source | C-nitro compound; caprolactams; organic heterotetracyclic compound | anti-HIV-1 agent; antineoplastic agent; apoptosis inducer; EC 2.7.11.1 (non-specific serine/threonine protein kinase) inhibitor; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor; EC 2.7.11.26 (tau-protein kinase) inhibitor |
quercetin | 7-hydroxyflavonol; pentahydroxyflavone | antibacterial agent; antineoplastic agent; antioxidant; Aurora kinase inhibitor; chelator; EC 1.10.99.2 [ribosyldihydronicotinamide dehydrogenase (quinone)] inhibitor; geroprotector; phytoestrogen; plant metabolite; protein kinase inhibitor; radical scavenger | |
apigenin | Chamomile: Common name for several daisy-like plants (MATRICARIA; TRIPLEUROSPERMUM; ANTHEMIS; CHAMAEMELUM) native to Europe and Western Asia, now naturalized in the United States and Australia. | trihydroxyflavone | antineoplastic agent; metabolite |
luteolin | 3'-hydroxyflavonoid; tetrahydroxyflavone | angiogenesis inhibitor; anti-inflammatory agent; antineoplastic agent; apoptosis inducer; c-Jun N-terminal kinase inhibitor; EC 2.3.1.85 (fatty acid synthase) inhibitor; immunomodulator; nephroprotective agent; plant metabolite; radical scavenger; vascular endothelial growth factor receptor antagonist | |
kaempferol | 7-hydroxyflavonol; flavonols; tetrahydroxyflavone | antibacterial agent; geroprotector; human blood serum metabolite; human urinary metabolite; human xenobiotic metabolite; plant metabolite | |
harmine | harmine : A harmala alkaloid in which the harman skeleton is methoxy-substituted at C-7. Harmine: Alkaloid isolated from seeds of PEGANUM HARMALA; ZYGOPHYLLACEAE. It is identical to banisterine, or telepathine, from Banisteria caapi and is one of the active ingredients of hallucinogenic drinks made in the western Amazon region from related plants. It has no therapeutic use, but (as banisterine) was hailed as a cure for postencephalitic PARKINSON DISEASE in the 1920's. | harmala alkaloid | anti-HIV agent; EC 1.4.3.4 (monoamine oxidase) inhibitor; metabolite |
aureusidin | aureusidin : A hydroxyaurone that is aurone substituted by hydroxy groups at positions 4, 6, 3' and 4' respectively. aureusidin: structure in first source | hydroxyaurone | plant metabolite |
sulfuretin | sulfuretin: the chalcone C ring closes into a 5 instead of the more typical 6 membered ring leaving a phenyl methane at the 2 position instead of the typical phenyl | 1-benzofurans | |
chrysin | chrysin : A dihydroxyflavone in which the two hydroxy groups are located at positions 5 and 7. | 7-hydroxyflavonol; dihydroxyflavone | anti-inflammatory agent; antineoplastic agent; antioxidant; EC 2.7.11.18 (myosin-light-chain kinase) inhibitor; hepatoprotective agent; plant metabolite |
cupressuflavone | cupressuflavone : A biflavonoid that is obtained by oxidative coupling of two molecules of apigenin resulting in a bond between positions C-8 of the two chromene rings respectively. Isolated from Cupressus sempervirens and Juniperus occidentalis, it exhibits free radical scavenging and antielastase activities. cupressuflavone: from Cupressus macrocarpa; structure in first source | biflavonoid; hydroxyflavone; ring assembly | EC 3.4.21.37 (leukocyte elastase) inhibitor; metabolite; radical scavenger |
fisetin | 3'-hydroxyflavonoid; 7-hydroxyflavonol; tetrahydroxyflavone | anti-inflammatory agent; antioxidant; EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor; geroprotector; metabolite; plant metabolite | |
demethylbellidifolin | bellidin : A member of the class of xanthones that is xanthone which is substituted by hydroxy groups at positions 1, 3, 5, and 8. A natural product found particularly in Iris nigricans and Gentiana campestris. demethylbellidifolin: protects the myocardium against damage due to ischemia-reperfusion in rats | tetrol; xanthones | antioxidant; EC 3.1.1.7 (acetylcholinesterase) inhibitor; metabolite; mutagen; radical scavenger |
hyperoside | quercetin 3-O-beta-D-galactopyranoside : A quercetin O-glycoside that is quercetin with a beta-D-galactosyl residue attached at position 3. Isolated from Artemisia capillaris, it exhibits hepatoprotective activity. | beta-D-galactoside; monosaccharide derivative; quercetin O-glycoside; tetrahydroxyflavone | hepatoprotective agent; plant metabolite |
alvocidib | alvocidib : A synthetic dihydroxyflavone that is 5,7-dihydroxyflavone which is substituted by a 3-hydroxy-1-methylpiperidin-4-yl group at position 8 and by a chlorine at the 2' position (the (-)-3S,4R stereoisomer). A cyclin-dependent kinase 9 (CDK9) inhibitor, it has been studied for the treatment of acute myeloid leukaemia, arthritis and atherosclerotic plaque formation. alvocidib: structure given in first source | dihydroxyflavone; hydroxypiperidine; monochlorobenzenes; tertiary amino compound | antineoplastic agent; antirheumatic drug; apoptosis inducer; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor |
aftin-4 | aftin-4: increases production of amyloid-beta protein (1-42) | ||
su 9516 | |||
arcyriaflavin a | arcyriaflavin A: from marine ascidian, Eudistoma sp.; structure given in first source | indolocarbazole | |
palbociclib | aminopyridine; aromatic ketone; cyclopentanes; piperidines; pyridopyrimidine; secondary amino compound; tertiary amino compound | antineoplastic agent; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor | |
olomoucine ii | olomoucine II: structure in first source | ||
manzamine a | manzamine A : An alkaloid of the class of beta-carbolines isolated from Haliclona and Acanthostrongylophora. It exhibits inhibitory activity against Glycogen Synthase Kinase-3 (EC 2.7.11.26). manzamine A: RN given refers to (1R-(1R*,9Z,13S*,13aR*,20aR*,21aR*)-isomer; RN for cpd without isomeric designation not avail 12/92 | alkaloid; beta-carbolines; isoquinolines | animal metabolite; anti-HSV-1 agent; antimalarial; antineoplastic agent; EC 2.7.11.26 (tau-protein kinase) inhibitor; marine metabolite |
1-azakenpaullone | 1-azakenpaullone : An organic heterotetracyclic compound that is 7,12-dihydropyrido[3',2':2,3]azepino[4,5-b]indole substituted at positions 6 and 9 by oxo and bromo groups respectively. | lactam; organic heterotetracyclic compound; organobromine compound; organonitrogen heterocyclic compound | EC 2.7.11.26 (tau-protein kinase) inhibitor; Wnt signalling activator |
cvt 313 | CVT 313: a potent inhibitor of CDK2 that prevents neointimal proliferation; structure given in first source | ||
leucettamine b | leucettamine B: a protein kinase inhibitor isolated from the marine sponge Leucetta microraphis; structure in first source | ||
nu 6140 | 4-(6-cyclohexylmethoxy-9H-purin-2-ylamino)-N,N-diethylbenzamide: a cyclin-dependent kinase inhibitor; structure in first source | ||
meridianin a | meridianin A: structure in first source | ||
rgb 286638 | |||
at 7519 | 4-(2,6-dichlorobenzamido)-N-(piperidin-4-yl)-pyrazole-3-carboxamide : A member of the class of pryrazoles that is 4-amino-1H-pyrazole-3-carboxylic acid in which the primary amino group has been acylated by a 2,6-dichlorobenzoyl group and in which the carboxylic acid has been converted into a carboxamide by formal condensation with the primary amino group of 4-aminopiperidine. | dichlorobenzene; piperidines; pyrazoles; secondary carboxamide | antineoplastic agent; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor |
pha 848125 | N,1,4,4-tetramethyl-8-((4-(4-methylpiperazin-1-yl)phenyl)amino)-4,5-dihydro-1H-pyrazolo(4,3-h)quinazoline-3-carboxamide: a cyclin dependent kinase inhibitor | ||
14-methyl-20-oxa-5,7,14,26-tetraazatetracyclo(19.3.1.1(2,6).1(8,12))heptacosa-1(25),2(26),3,5,8(27),9,11,16,21,23-decaene | 14-methyl-20-oxa-5,7,14,26-tetraazatetracyclo(19.3.1.1(2,6).1(8,12))heptacosa-1(25),2(26),3,5,8(27),9,11,16,21,23-decaene: has antineoplastic activity; also inhibits Fms-like tyrosine kinase-3; structure in first source | ||
meriolin 3 | meriolin 3: a cell death-inducing kinase inhibitor; structure in first source | ||
amg 458 | 1-(2-hydroxy-2-methylpropyl)-N-(5-(7-methoxyquinolin-4-yloxy)pyridin-2-yl)-5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxamide: a c-met inhibitor; structure in first source | ||
cink4 | CINK4: cyclin-dependent kinase 4 inhibitor; may have tumor suppression activity; structure in first source | indoles | |
ldc067 | |||
(R)-DRF053 | (R)-DRF053 : A member of the class of 2,6-diaminopurines that is 2,6-diamiopurine which is substituted by an isopropyl group at position 9 and in which the amino groups at positions 2 and 6 are substituted by a 1-hydroxybutan-2-yl and 3-(pyridin-2-yl)phenyl groups, respectively (the R enantiomer). A cyclin dependent kinase inhibitor, widely used as its hydrochloride hydrate. | 2,6-diaminopurines; phenylpyridine; primary alcohol; secondary amino compound | EC 2.7.11.22 (cyclin-dependent kinase) inhibitor |
ribociclib | ribociclib: inhibits both CDK4 and CDK6 | ||
bay 1000394 | roniciclib: an antineoplastic agent that inhibits cyclin-dependent kinases; structure in first source | ||
pha 793887 | piperidinecarboxamide | ||
abemaciclib | |||
dinaciclib | pyrazolopyrimidine | ||
nms p937 | NMS P937: a polo-like kinase 1 inhibitor; structure in first source | ||
bs-181 | BS-181: a CDK7 inhibitor with antineoplastic activity | pyrazolopyrimidine | |
on123300 | ON123300: a protein kinase inhibitor; structure in first source | ||
chr-6494 | |||
((5z)5-(1,3-benzodioxol-5-yl)methylene-2-phenylamino-3,5-dihydro-4h-imidazol-4-one) | leucettine L41 : A member of the class of benzodioxoles that is 1,3-benzodioxole substituted by a (2-anilino-5-oxo-1,5-dihydro-4H-imidazol-4-ylidene)methyl group at position 5. It is an inhibitor of DYRK1A, DYRK2, CLK1, and CLK3 (IC50s = 0.04, 0.035, 0.015, and 4.5 muM, respectively). | benzodioxoles; imidazolone; substituted aniline | autophagy inducer; EC 2.7.11.22 (cyclin-dependent kinase) inhibitor; EC 2.7.12.1 (dual-specificity kinase) inhibitor; neuroprotective agent; nootropic agent |
ro 3306 | RO 3306: structure in first source | ||
hymenialdisine | |||
7-bromoindirubin-3'-oxime | 7-bromoindirubin-3'-oxime: has mild protein kinase inhibitory activity; induces caspase-independent cell death; structure in first source | ||
debromohymenialdisine |