Striated Muscle Contraction (Homo sapiens)

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Striated muscle contraction is a process whereby force is generated within striated muscle tissue, resulting in a change in muscle geometry, or in short, increased force being exerted on the tendons. Force generation involves a chemo-mechanical energy conversion step that is carried out by the actin/myosin complex activity, which generates force through ATP hydrolysis. Striated muscle is a type of muscle composed of myofibrils, containing repeating units called sarcomeres, in which the contractile myofibrils are arranged in parallel to the axis of the cell, resulting in transverse or oblique striations observable at the level of the light microscope.
Here striated muscle contraction is represented on the basis of calcium binding to the troponin complex, which exposes the active sites of actin. Once the active sites of actin are exposed, the myosin complex bound to ADP can bind actin and the myosin head can pivot, pulling the thin actin and thick myosin filaments past one another. Once the myosin head pivots, ADP is ejected, a fresh ATP can be bound and the energy from the hydrolysis of ATP to ADP is channeled into kinetic energy by resetting the myosin head. With repeated rounds of this cycle the sarcomere containing the thin and thick filaments effectively shortens, forming the basis of muscle contraction. View original pathway at:Reactome.


Pathway is converted from Reactome ID: 390522
Reactome version: 61
Reactome Author 
Reactome Author: Gillespie, Marc E

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Ontology Terms



  1. Cooke R.; ''The sliding filament model: 1972-2004.''; PubMed
  2. Szent-Györgyi AG.; ''The early history of the biochemistry of muscle contraction.''; PubMed
  3. HUXLEY AF, NIEDERGERKE R.; ''Structural changes in muscle during contraction; interference microscopy of living muscle fibres.''; PubMed
  4. Gordon AM, Homsher E, Regnier M.; ''Regulation of contraction in striated muscle.''; PubMed
  5. HUXLEY AF, NIEDERGERKE R.; ''Measurement of muscle striations in stretch and contraction.''; PubMed


93771view13:35, 16 August 2017ReactomeTeamreactome version 61
93296view11:19, 9 August 2017ReactomeTeamreactome version 61
87838view11:47, 25 July 2016MirellaKalafatiOntology Term : 'regulatory pathway' added !
86381view09:16, 11 July 2016ReactomeTeamNew pathway

External references


View all...
NameTypeDatabase referenceComment
ACTN2 ProteinP35609 (Uniprot-TrEMBL)
ACTN3 ProteinQ08043 (Uniprot-TrEMBL)
ADP MetaboliteCHEBI:16761 (ChEBI)
ADP:Calcium Bound

Sarcomere Protein

ComplexR-HSA-390591 (Reactome)
ADPMetaboliteCHEBI:16761 (ChEBI)
ATP MetaboliteCHEBI:15422 (ChEBI)
ATP:Calcium Bound

Sarcomere Protein

ComplexR-HSA-390596 (Reactome)
ATPMetaboliteCHEBI:15422 (ChEBI)
Ca2+ MetaboliteCHEBI:29108 (ChEBI)
Ca2+MetaboliteCHEBI:29108 (ChEBI)
Calcium Bound

Sarcomere Protein

ComplexR-HSA-390592 (Reactome)
DES ProteinP17661 (Uniprot-TrEMBL)
DMD ProteinP11532 (Uniprot-TrEMBL)
Inactive Sarcomere Protein ComplexComplexR-HSA-390590 (Reactome)
MYBPC1 ProteinQ00872 (Uniprot-TrEMBL)
MYBPC2 ProteinQ14324 (Uniprot-TrEMBL)
MYBPC3 ProteinQ14896 (Uniprot-TrEMBL)
MYH3 ProteinP11055 (Uniprot-TrEMBL)
MYH6 ProteinP13533 (Uniprot-TrEMBL)
MYH8 ProteinP13535 (Uniprot-TrEMBL)
MYL1 ProteinP05976 (Uniprot-TrEMBL)
MYL2 ProteinP10916 (Uniprot-TrEMBL)
MYL3 ProteinP08590 (Uniprot-TrEMBL)
MYL4 ProteinP12829 (Uniprot-TrEMBL)
Myosin ComplexComplexR-HSA-390575 (Reactome)
NEB ProteinP20929 (Uniprot-TrEMBL)
PiMetaboliteCHEBI:18367 (ChEBI)
TCAP ProteinO15273 (Uniprot-TrEMBL)
TMOD1 ProteinP28289 (Uniprot-TrEMBL)
TMOD2 ProteinQ9NZR1 (Uniprot-TrEMBL)
TMOD3 ProteinQ9NYL9 (Uniprot-TrEMBL)
TMOD4 ProteinQ9NZQ9 (Uniprot-TrEMBL)
TNNC1 ProteinP63316 (Uniprot-TrEMBL)
TNNC2 ProteinP02585 (Uniprot-TrEMBL)
TNNI1 ProteinP19237 (Uniprot-TrEMBL)
TNNI2 ProteinP48788 (Uniprot-TrEMBL)
TNNI3 ProteinP19429 (Uniprot-TrEMBL)
TNNT1 ProteinP13805 (Uniprot-TrEMBL)
TNNT2 ProteinP45379 (Uniprot-TrEMBL)
TNNT3 ProteinP45378 (Uniprot-TrEMBL)
TPM1 ProteinP09493 (Uniprot-TrEMBL)
TPM2 ProteinP07951 (Uniprot-TrEMBL)
TPM3 ProteinP06753 (Uniprot-TrEMBL)
TPM4 ProteinP67936 (Uniprot-TrEMBL)
TTN ProteinQ8WZ42 (Uniprot-TrEMBL)
VIM ProteinP08670 (Uniprot-TrEMBL)
alpha Actin Chain R-HSA-390576 (Reactome)

Annotated Interactions

View all...
SourceTargetTypeDatabase referenceComment
ADP:Calcium Bound

Sarcomere Protein

ArrowR-HSA-390593 (Reactome)
ADP:Calcium Bound

Sarcomere Protein

R-HSA-390597 (Reactome)
ADPArrowR-HSA-390597 (Reactome)
ATP:Calcium Bound

Sarcomere Protein

ArrowR-HSA-390598 (Reactome)
ATP:Calcium Bound

Sarcomere Protein

R-HSA-390593 (Reactome)
ATPR-HSA-390598 (Reactome)
Ca2+R-HSA-390595 (Reactome)
Calcium Bound

Sarcomere Protein

ArrowR-HSA-390595 (Reactome)
Calcium Bound

Sarcomere Protein

ArrowR-HSA-390597 (Reactome)
Calcium Bound

Sarcomere Protein

R-HSA-390598 (Reactome)
Inactive Sarcomere Protein ComplexR-HSA-390595 (Reactome)
Myosin Complexmim-catalysisR-HSA-390593 (Reactome)
PiArrowR-HSA-390593 (Reactome)
R-HSA-390593 (Reactome) The cleft closes like a clam shell around the ATP molecule, triggering a large shape change that causes the myosin head to release actin and be displaced along the actin filament by a distance of about 5 nm. Hydrolysis of ATP occurs, but the ADP remains tightly bound to the protein.
R-HSA-390595 (Reactome) Troponin (Tn) is the central regulatory protein of striated muscle contraction. Tn consists of three components: troponin I (TNNI3; the inhibitor of actomyosin ATPase), Tn-T (which contains the binding site for tropomyosin) and troponin C (TNNC1, Tn-C). The binding of calcium to TNNC1 abolishes the inhibitory action of Tn on actin filaments. At the start of the striated muscle contraction cycle, a myosin head lacking a bound nucleotide is locked tightly onto an actin filament in a rigor conformation. TNNC1 binds four calcium ions. In an actively contracting muscle this state is very short-lived, being rapidly terminated by the binding of a molecule of ATP.
R-HSA-390597 (Reactome) The weak binding of the myosin head to the new site on the actin filament causes release of the inorganic phosphate produced by ATP hydrolysis, concomitantly with the tight binding of the head to actin. This release triggers the power stroke, a force-generating change in the shape during which the head regains its original conformation. In the course of the power stroke, the head loses its bound ADP, thereby returning to the start of a new cycle.
R-HSA-390598 (Reactome) A molecule of ATP binds to the large cleft on the side of the myosin head farthest from the actin filament and immediately causes a slight change in the conformation of the domains that make up the actin-binding site. This reduces the affinity of the myosin head for actin and allows it to move along the filament.
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