Pathway Human Homo sapiens

Cardiac conduction

R-HSA-5576891 in Reactome release 97: under Muscle contraction, with 132 genes placed in it by the mapping files and 7 child pathways in the hierarchy.

The same number in the other species

Reactome writes the mouse and rat events it infers from a human pathway under the human number with the species token. A door opens only where that species' own list in this release holds the id: R-MMU-5576891 (mouse), R-RNO-5576891 (rat). Whether the event was inferred from this one is what the record says.

The record
The genes
Parents and children

Scripts are off

This page reads the pathway's record from its source while you read the rest; with scripts off the card stays at its loading line. Reload with scripts on to see it, or open the source's own page from the link in the card.

01The record

Reactome's own record of this pathway

What this tells you

The pathway list, the hierarchy and the genes on this page are read from the files Reactome publishes for Reactome release 97, built into this site on 2026-09-09: the pathway list, the hierarchy relationship file and the two gene mapping files. The record card is the one live read, Reactome's own record of this pathway.

Reactome's download page describes the mapping files: Mapping files link the source database identifier to the lowest level pathway diagram or subset of the pathway, all levels of the pathway hierarchy or database identifier to all reactions. [R13] The gene list here is the all-levels mapping of NCBI Gene ids, filled from the all-levels mapping of Ensembl ids where the NCBI file has no row for a gene; each row names which file it came from by the shape of its source id. Each row carries the evidence codes the file writes for it, as written and unranked, and both where the file writes both; no page of Reactome's documentation the survey read defines the codes, so this page does not expand them. A gene id the identity files do not name is kept as the source's own id with no door rather than turned into a symbol.

On citing what a search finds, Reactome says: It should be remembered that while we strive to contain the most current and accurate data, Reactome should not be used in citations where other primary sources of information are available. [R12] The record card prints the literature Reactome attaches to a curated pathway for that reason. The data are public domain: All data in the Reactome database and files derived from that data are licensed under the Creative Commons Public Domain Dedication (CC0). User may copy, modify, and distribute these data, even for commercial purposes, without asking for permission. Attribution is encouraged but not required. [R10] The pathway illustrations are licensed apart, under CC BY 4.0, and none is shown here.

A gene on this list is one Reactome places in this pathway in this release, and that is all the row says: it does not say the gene is expressed in a tissue or associated with a disease, which are the other two explorers' questions, read from other sources. Reactome's papers of record are [R01] [R02].

[R01] Ragueneau E, Gong C, Sinquin P, Sevilla C, Beavers D, Grentner A, et al. (2026). The Reactome Knowledgebase 2026. Nucleic Acids Research 54:D673-D681. PMID 41251150, doi 10.1093/nar/gkaf1223.
[R02] Milacic M, Beavers D, Conley P, Gong C, Gillespie M, Griss J, et al. (2024). The Reactome Pathway Knowledgebase 2024. Nucleic Acids Research 52:D672-D678. PMID 37941124, doi 10.1093/nar/gkad1025.
[R10] Reactome, reactome.org. License Agreement. https://reactome.org/license, read 2026-09-09.
[R12] Reactome, reactome.org. Citing us. https://reactome.org/cite, read 2026-09-09.
[R13] Reactome, reactome.org. Download. https://reactome.org/download-data, read 2026-09-09.

Stable id: R-HSA-5576891.6
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2015-12-15
Last updated: 2022-06-09
Events inside: 7, counted from the record

The normal sequence of contraction of atria and ventricles of the heart require activation of groups of cardiac cells. The mechanism must elicit rapid changes in heart rate and respond to changes in autonomic tone. The cardiac action potential controls these functions. Action potentials are generated by the movement of ions through transmembrane ion channels in cardiac cells. Like skeletal myocytes (and axons), in the resting state, a given cardiac myocyte has a negative membrane potential. In both muscle types, after a delay (the absolute refractory period), K+ channels reopen and the resulting flow of K+ out of the cell causes repolarisation. The voltage-gated Ca2+ channels on the cardiac sarcolemma membrane are generally triggered by an influx of Na+ during phase 0 of the action potential. Cardiac muscle cells are so tightly bound that when one of these cells is excited the action potential spreads to all of them. The standard model used to understand the cardiac action potential is the action potential of the ventricular myocyte (Park & Fishman 2011, Grant 2009).

The action potential has 5 phases (numbered 0-4). Phase 4 describes the membrane potential when a cell is not being stimulated. The normal resting potential in the ventricular myocardium is between -85 to -95 mV. The K+ gradient across the cell membrane is the key determinant in the normal resting potential. Phase 0 is the rapid depolarisation phase in which electrical stimulation of a cell opens the closed, fast Na+ channels, causing a large influx of Na+ creating a Na+ current (INa+). This causes depolarisation of the cell. The slope of phase 0 represents the maximum rate of potential change and differs in contractile and pacemaker cells. Phase 1 is the inactivation of the fast Na+ channels. The transient net outward current causing the small downward deflection (the "notch" of the action potetial) is due to the movement of K+ and Cl- ions. In pacemaker cells, this phase is due to rapid K+ efflux and closure of L-type Ca2+ channels. Phase 2 is the plateau phase which is sustained by a balance of Ca2+ influx and K+ efflux. This phase sustains muscle contraction. Phase 3 of the action potential is where a concerted action of two outward delayed currents brings about repolarisation back down to the resting potential (Bartos et al. 2015).

Literature Reactome attaches

The cardiac conduction systemCirculation, 2011, vol. 123, p. 904-15PubMed 21357845
Cardiac ion channelsCirc Arrhythm Electrophysiol, 2009, vol. 2, p. 185-94PubMed 19808464
Ion Channels in the HeartCompr Physiol, 2015, vol. 5, p. 1423-64PubMed 26140724

Reactome's record lists 14 orthologous events, R-RNO-5576891 (Rattus norvegicus), R-MMU-5576891 (Mus musculus) among the species this site serves, and 12 in species this site opens no page for.

Reactome ContentService, this pathway's record · Reactome v97 · read 2026-10-02 ET · Reactome pathway browser"Cardiac conduction". Reactome, release 97, https://reactome.org/PathwayBrowser/#/R-HSA-5576891 with StableID: R-HSA-5576891.6 (accessed 2026-10-02 ET). Reactome version 97 (CC0).

Reading this pathway's record from Reactome (the pathway record).Still reading. A first read of a pathway can take a while; this page waits up to 35 seconds for it, and its scripts then bring in the panel, or a line saying what did not arrive.

02The genes

Genes Reactome places in this human pathway

The mapping files place 132 genes in this human pathway; showing 1 to 100, in pages of 100, sorted by symbol for reading. The order carries no ranking.

Genes Reactome places in this human pathway, page 1 of 2
Gene	Authority id	Mapping file id	Evidence codes
GeneABCC9	AuthorityHGNC:60	Mapping file id10060 NCBI file	EvidenceTAS
GeneAHCYL1	AuthorityHGNC:344	Mapping file id10768 NCBI file	EvidenceIEA, TAS
GeneAKAP9	AuthorityHGNC:379	Mapping file id10142 NCBI file	EvidenceTAS
GeneASPH	AuthorityHGNC:757	Mapping file id444 NCBI file	EvidenceTAS
GeneATP1A1	AuthorityHGNC:799	Mapping file id476 NCBI file	EvidenceTAS
GeneATP1A2	AuthorityHGNC:800	Mapping file id477 NCBI file	EvidenceTAS
GeneATP1A3	AuthorityHGNC:801	Mapping file id478 NCBI file	EvidenceTAS
GeneATP1A4	AuthorityHGNC:14073	Mapping file id480 NCBI file	EvidenceTAS
GeneATP1B1	AuthorityHGNC:804	Mapping file id481 NCBI file	EvidenceTAS
GeneATP1B2	AuthorityHGNC:805	Mapping file id482 NCBI file	EvidenceTAS
GeneATP1B3	AuthorityHGNC:806	Mapping file id483 NCBI file	EvidenceTAS
GeneATP2A1	AuthorityHGNC:811	Mapping file id487 NCBI file	EvidenceTAS
GeneATP2A2	AuthorityHGNC:812	Mapping file id488 NCBI file	EvidenceTAS
GeneATP2A3	AuthorityHGNC:813	Mapping file id489 NCBI file	EvidenceTAS
GeneATP2B1	AuthorityHGNC:814	Mapping file id490 NCBI file	EvidenceTAS
GeneATP2B2	AuthorityHGNC:815	Mapping file id491 NCBI file	EvidenceTAS
GeneATP2B3	AuthorityHGNC:816	Mapping file id492 NCBI file	EvidenceTAS
GeneATP2B4	AuthorityHGNC:817	Mapping file id493 NCBI file	EvidenceTAS
GeneCACNA1C	AuthorityHGNC:1390	Mapping file id775 NCBI file	EvidenceTAS
GeneCACNA2D2	AuthorityHGNC:1400	Mapping file id9254 NCBI file	EvidenceTAS
GeneCACNB1	AuthorityHGNC:1401	Mapping file id782 NCBI file	EvidenceTAS
GeneCACNB2	AuthorityHGNC:1402	Mapping file id783 NCBI file	EvidenceTAS
GeneCACNG4	AuthorityHGNC:1408	Mapping file id27092 NCBI file	EvidenceTAS
GeneCACNG6	AuthorityHGNC:13625	Mapping file id59285 NCBI file	EvidenceTAS
GeneCACNG7	AuthorityHGNC:13626	Mapping file id59284 NCBI file	EvidenceTAS
GeneCACNG8	AuthorityHGNC:13628	Mapping file id59283 NCBI file	EvidenceTAS
GeneCALM1	AuthorityHGNC:1442	Mapping file id801 NCBI file	EvidenceTAS
GeneCALM2	AuthorityHGNC:1445	Mapping file id805 NCBI file	EvidenceTAS
GeneCALM3	AuthorityHGNC:1449	Mapping file id808 NCBI file	EvidenceTAS
GeneCAMK2A	AuthorityHGNC:1460	Mapping file id815 NCBI file	EvidenceTAS
GeneCAMK2B	AuthorityHGNC:1461	Mapping file id816 NCBI file	EvidenceTAS
GeneCAMK2D	AuthorityHGNC:1462	Mapping file id817 NCBI file	EvidenceTAS
GeneCAMK2G	AuthorityHGNC:1463	Mapping file id818 NCBI file	EvidenceTAS
GeneCASQ1	AuthorityHGNC:1512	Mapping file id844 NCBI file	EvidenceTAS
GeneCASQ2	AuthorityHGNC:1513	Mapping file id845 NCBI file	EvidenceTAS
GeneCES1	AuthorityHGNC:1863	Mapping file id1066 NCBI file	EvidenceTAS
GeneCLIC2	AuthorityHGNC:2063	Mapping file id1193 NCBI file	EvidenceTAS
GeneCORIN	AuthorityHGNC:19012	Mapping file id10699 NCBI file	EvidenceTAS
GeneDMPK	AuthorityHGNC:2933	Mapping file id1760 NCBI file	EvidenceTAS
GeneFGF11	AuthorityHGNC:3667	Mapping file id2256 NCBI file	EvidenceTAS
GeneFGF12	AuthorityHGNC:3668	Mapping file id2257 NCBI file	EvidenceTAS
GeneFGF13	AuthorityHGNC:3670	Mapping file id2258 NCBI file	EvidenceTAS
GeneFGF14	AuthorityHGNC:3671	Mapping file id2259 NCBI file	EvidenceTAS
GeneFKBP1B	AuthorityHGNC:3712	Mapping file id2281 NCBI file	EvidenceTAS
GeneFXYD1	AuthorityHGNC:4025	Mapping file id5348 NCBI file	EvidenceTAS
GeneFXYD2	AuthorityHGNC:4026	Mapping file id486 NCBI file	EvidenceTAS
GeneFXYD3	AuthorityHGNC:4027	Mapping file id5349 NCBI file	EvidenceTAS
GeneFXYD4	AuthorityHGNC:4028	Mapping file id53828 NCBI file	EvidenceTAS
GeneFXYD6	AuthorityHGNC:4030	Mapping file id53826 NCBI file	EvidenceTAS
GeneFXYD7	AuthorityHGNC:4034	Mapping file id53822 NCBI file	EvidenceTAS
GeneGATA4	AuthorityHGNC:4173	Mapping file id2626 NCBI file	EvidenceTAS
GeneHIPK1	AuthorityHGNC:19006	Mapping file id204851 NCBI file	EvidenceTAS
GeneHIPK2	AuthorityHGNC:14402	Mapping file id28996 NCBI file	EvidenceTAS
GeneITPR1	AuthorityHGNC:6180	Mapping file id3708 NCBI file	EvidenceIEA, TAS
GeneITPR2	AuthorityHGNC:6181	Mapping file id3709 NCBI file	EvidenceIEA, TAS
GeneITPR3	AuthorityHGNC:6182	Mapping file id3710 NCBI file	EvidenceIEA, TAS
GeneKAT2B	AuthorityHGNC:8638	Mapping file id8850 NCBI file	EvidenceTAS
GeneKCNA5	AuthorityHGNC:6224	Mapping file id3741 NCBI file	EvidenceTAS
GeneKCND1	AuthorityHGNC:6237	Mapping file id3750 NCBI file	EvidenceTAS
GeneKCND2	AuthorityHGNC:6238	Mapping file id3751 NCBI file	EvidenceTAS
GeneKCND3	AuthorityHGNC:6239	Mapping file id3752 NCBI file	EvidenceTAS
GeneKCNE1	AuthorityHGNC:6240	Mapping file id3753 NCBI file	EvidenceTAS
GeneKCNE2	AuthorityHGNC:6242	Mapping file id9992 NCBI file	EvidenceTAS
GeneKCNE3	AuthorityHGNC:6243	Mapping file id10008 NCBI file	EvidenceTAS
GeneKCNE4	AuthorityHGNC:6244	Mapping file id23704 NCBI file	EvidenceTAS
GeneKCNE5	AuthorityHGNC:6241	Mapping file id23630 NCBI file	EvidenceTAS
GeneKCNH2	AuthorityHGNC:6251	Mapping file id3757 NCBI file	EvidenceTAS
GeneKCNIP1	AuthorityHGNC:15521	Mapping file id30820 NCBI file	EvidenceTAS
GeneKCNIP2	AuthorityHGNC:15522	Mapping file id30819 NCBI file	EvidenceTAS
GeneKCNIP3	AuthorityHGNC:15523	Mapping file id30818 NCBI file	EvidenceTAS
GeneKCNIP4	AuthorityHGNC:30083	Mapping file id80333 NCBI file	EvidenceTAS
GeneKCNJ11	AuthorityHGNC:6257	Mapping file id3767 NCBI file	EvidenceTAS
GeneKCNJ12	AuthorityHGNC:6258	Mapping file id3768 NCBI file	EvidenceTAS
GeneKCNJ14	AuthorityHGNC:6260	Mapping file id3770 NCBI file	EvidenceTAS
GeneKCNJ2	AuthorityHGNC:6263	Mapping file id3759 NCBI file	EvidenceTAS
GeneKCNJ4	AuthorityHGNC:6265	Mapping file id3761 NCBI file	EvidenceTAS
GeneKCNK1	AuthorityHGNC:6272	Mapping file id3775 NCBI file	EvidenceTAS
GeneKCNK10	AuthorityHGNC:6273	Mapping file id54207 NCBI file	EvidenceTAS
GeneKCNK12	AuthorityHGNC:6274	Mapping file id56660 NCBI file	EvidenceTAS
GeneKCNK13	AuthorityHGNC:6275	Mapping file id56659 NCBI file	EvidenceTAS
GeneKCNK15	AuthorityHGNC:13814	Mapping file id60598 NCBI file	EvidenceTAS
GeneKCNK16	AuthorityHGNC:14464	Mapping file id83795 NCBI file	EvidenceTAS
GeneKCNK17	AuthorityHGNC:14465	Mapping file id89822 NCBI file	EvidenceTAS
GeneKCNK18	AuthorityHGNC:19439	Mapping file id338567 NCBI file	EvidenceTAS
GeneKCNK2	AuthorityHGNC:6277	Mapping file id3776 NCBI file	EvidenceTAS
GeneKCNK3	AuthorityHGNC:6278	Mapping file id3777 NCBI file	EvidenceTAS
GeneKCNK4	AuthorityHGNC:6279	Mapping file id50801 NCBI file	EvidenceTAS
GeneKCNK5	AuthorityHGNC:6280	Mapping file id8645 NCBI file	EvidenceTAS
GeneKCNK6	AuthorityHGNC:6281	Mapping file id9424 NCBI file	EvidenceTAS
GeneKCNK7	AuthorityHGNC:6282	Mapping file id10089 NCBI file	EvidenceTAS
GeneKCNK9	AuthorityHGNC:6283	Mapping file id51305 NCBI file	EvidenceTAS
GeneKCNQ1	AuthorityHGNC:6294	Mapping file id3784 NCBI file	EvidenceTAS
GeneMME	AuthorityHGNC:7154	Mapping file id4311 NCBI file	EvidenceTAS
GeneNKX2-5	AuthorityHGNC:2488	Mapping file id1482 NCBI file	EvidenceTAS
GeneNOS1	AuthorityHGNC:7872	Mapping file id4842 NCBI file	EvidenceTAS
GeneNPPA	AuthorityHGNC:7939	Mapping file id4878 NCBI file	EvidenceTAS
GeneNPPC	AuthorityHGNC:7941	Mapping file id4880 NCBI file	EvidenceTAS
GeneNPR1	AuthorityHGNC:7943	Mapping file id4881 NCBI file	EvidenceTAS
GeneNPR2	AuthorityHGNC:7944	Mapping file id4882 NCBI file	EvidenceTAS
GeneORAI1	AuthorityHGNC:25896	Mapping file id84876 NCBI file	EvidenceIEA

Evidence codes on this page: IEA, TAS, as the mapping file writes them; a row carrying two was written twice by the file, once under each. The mapping file id says which file placed the gene: an NCBI Gene id from NCBI2Reactome_All_Levels.txt, an Ensembl gene id from Ensembl2Reactome_All_Levels.txt. The two files can disagree about a code, so a row's codes are the one file's view. Measured by this site's build over this release on 2026-09-09: of the 138,908 human pathway-gene pairs both files place, 207 (0.149 per cent, over 47 genes) carry TAS in the Ensembl file where the NCBI rows carry IEA alone.

Reactome mapping files, the human rows for this pathway · Reactome release 97 · read 2026-09-09 · Reactome downloads"NCBI2Reactome_All_Levels.txt" and "Ensembl2Reactome_All_Levels.txt", Reactome, release 97, https://reactome.org/download-data/ (date of access 2026-09-09). Data CC0; attribution encouraged.

03The hierarchy

Parents and children in this release's hierarchy

Parents

Muscle contractionR-HSA-397014205 genes

Children

Reactome's hierarchy is a graph rather than a tree: a pathway can sit under more than one parent, and the gene counts are each pathway's own placements at every level under it, so a parent's count is not the sum of its children's.

Reactome, the human pathway list and hierarchy relationship file · Reactome release 97 · read 2026-09-09 · Reactome downloads"ReactomePathways.txt" and "ReactomePathwaysRelation.txt", Reactome, release 97, https://reactome.org/download-data/ (date of access 2026-09-09). Data CC0; attribution encouraged.