Pathway Human Homo sapiens

Elevation of cytosolic Ca2+ levels

R-HSA-139853 in Reactome release 97: under Platelet calcium homeostasis, with 16 genes placed in it by the mapping files and 0 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-139853 (mouse), R-RNO-139853 (rat). Whether the event was inferred from this one is what the record says.

The record
The genes
Parents and children

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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-139853.5
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2004-10-27
Last updated: 2016-12-21
Events inside: 5, counted from the record

Activation of non- excitable cells involves the agonist-induced elevation of cytosolic Ca2+, an essential process for platelet activation. It occurs through Ca2+ release from intracellular stores and Ca2+ entry through the plasma membrane. Ca2+ store release involves phospholipase C (PLC)-mediated production of inositol-1,4,5-trisphosphate (IP3), which in turn stimulates IP3 receptor channels to release Ca2+ from intracellular stores. This is followed by Ca2+ entry into the cell through plasma membrane calcium channels, a process referred to as store-operated calcium entry (SOCE). Stromal interaction molecule 1 (STIM1), a Ca2+ sensor molecule in intracellular stores, and the four transmembrane channel protein Orai1 are the key players in platelet SOCE. Other major Ca2+ entry mechanisms are mediated by the direct receptor-operated calcium (ROC) channel, P2X1 and transient receptor potential channels (TRPCs).

Literature Reactome attaches

Intracellular calcium release from human platelets: different messengers for multiple storesTrends Cardiovasc Med, 2008, vol. 18, p. 57-61PubMed 18308196
Calcium signaling in plateletsJ Thromb Haemost, 2009, vol. 7, p. 1057-66PubMed 19422456
Calcium signalling in lymphocyte activation and diseaseNat Rev Immunol, 2007, vol. 7, p. 690-702PubMed 17703229

Reactome's record lists 11 orthologous events, R-RNO-139853 (Rattus norvegicus), R-MMU-139853 (Mus musculus) among the species this site serves, and 9 in species this site opens no page for.

Reactome ContentService, this pathway's record · Reactome v97 · read 2026-09-30 ET · Reactome pathway browser"Elevation of cytosolic Ca2+ levels". Reactome, release 97, https://reactome.org/PathwayBrowser/#/R-HSA-139853 with StableID: R-HSA-139853.5 (accessed 2026-09-30 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 16 genes in this human pathway; showing 1 to 16, in pages of 100, sorted by symbol for reading. The order carries no ranking.

Genes Reactome places in this human pathway, page 1 of 1
Gene	Authority id	Mapping file id	Evidence codes
GeneITPR1	AuthorityHGNC:6180	Mapping file id3708 NCBI file	EvidenceTAS
GeneITPR2	AuthorityHGNC:6181	Mapping file id3709 NCBI file	EvidenceTAS
GeneITPR3	AuthorityHGNC:6182	Mapping file id3710 NCBI file	EvidenceTAS
GeneORAI1	AuthorityHGNC:25896	Mapping file id84876 NCBI file	EvidenceIEA
GeneORAI2	AuthorityHGNC:21667	Mapping file id80228 NCBI file	EvidenceIEA
GeneP2RX1	AuthorityHGNC:8533	Mapping file id5023 NCBI file	EvidenceTAS
GeneP2RX2	AuthorityHGNC:15459	Mapping file id22953 NCBI file	EvidenceTAS
GeneP2RX3	AuthorityHGNC:8534	Mapping file id5024 NCBI file	EvidenceTAS
GeneP2RX4	AuthorityHGNC:8535	Mapping file id5025 NCBI file	EvidenceTAS
GeneP2RX5	AuthorityHGNC:8536	Mapping file id5026 NCBI file	EvidenceTAS
GeneP2RX6	AuthorityHGNC:8538	Mapping file id9127 NCBI file	EvidenceTAS
GeneP2RX7	AuthorityHGNC:8537	Mapping file id5027 NCBI file	EvidenceTAS
GeneSTIM1	AuthorityHGNC:11386	Mapping file id6786 NCBI file	EvidenceIEA
GeneTRPC3	AuthorityHGNC:12335	Mapping file id7222 NCBI file	EvidenceTAS
GeneTRPC6	AuthorityHGNC:12338	Mapping file id7225 NCBI file	EvidenceTAS
GeneTRPC7	AuthorityHGNC:20754	Mapping file id57113 NCBI file	EvidenceTAS

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

Platelet calcium homeostasisR-HSA-41836030 genes

Children

None: no pathway of this release's list names this one as a parent.

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.