Pathway Human Homo sapiens

PI Metabolism

R-HSA-1483255 in Reactome release 97: under Phospholipid metabolism, with 84 genes placed in it by the mapping files and 13 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-1483255 (mouse), R-RNO-1483255 (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-1483255.7
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2012-06-12
Last updated: 2023-03-29
Events inside: 14, counted from the record

Phosphatidylinositol (PI), a membrane phospholipid, can be reversibly phosphorylated at the 3, 4, and 5 positions of the inositol ring to generate seven phosphoinositides: phosphatidylinositol 3-phosphate (PI3P), phosphatidylinositol 4-phosphate (PI4P), phosphatidylinositol 5-phosphate (PI5P), phosphatidylinositol 3,4-bisphosphate PI(3,4)P2, phosphatidylinositol 4,5-bisphosphate PI(4,5)P2, phosphatidylinositol 3,5-bisphosphate PI(3,5)P2, and phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3). These seven phosphoinositides, which are heterogeneously distributed within cells, can serve as signature components of different intracellular compartment membranes and so help to mediate specificity of membrane interactions. Phosphoinositide levels are tightly regulated spatially and temporally by the action of various kinases and phosphatases whilst PI(4,5)P2 is also a substrate for phospholipase C. The differential localisation of each of these enzymes on specific compartment membranes ensures maintenance of the heterogeneous distribution of phosphoinositides despite the continuous membrane flow from one compartment to another.

PI is primarily synthesised in the endoplasmic reticulum from where the phospholipid is exported to other compartments via membrane traffic or via cytosolic phospholipid transfer proteins. Phosphorylation of PI to PI4P primarily occurs in the Golgi, where PI4P plays an important role in the biogenesis of transport vesicles such as the secretory vesicle involved in its transport to the plasma membrane. At this place, PI4P has a major function acting as a precursor of PI(4,5)P2, which is located predominantly at this membrane. PI(4,5)P2 binds and regulates a wide range of proteins that function on the cell surface and serves as a precursor for second messengers. Additionally, it helps define this membrane as a target for secretory vesicles, functions as a coreceptor in endocytic processes, and functions as a cofactor for actin nucleation.

At the plasma membrane, PI(4,5)P2 is further phosphorylated to PI(3,4,5)P3, another phosphoinositide with important signalling functions including stimulating cell survival and proliferation. The inositol 3-phosphatase, phosphatase and tensin homolog (PTEN) regenerates PI(4,5)P2, while the 5-phosphatases convert PI(3,4,5)P3 into the phosphoinositide, PI(3,4)P2, propagating the signal initiated by PI(3,4,5)P3. PI(3,4)P2 is further dephosphorylated in the endocytic pathway by inositol 4-phosphatases to PI3P, the signature phosphoinositide of the early endosomal compartment and a ligand for numerous endosomal proteins. However, the bulk of PI3P is generated directly in the endosomes by phosphorylation of PI. The subsequent endosomal phosphorylation of PI3P to PI(3,5)P2 is believed to generate docking sites for recruitment of cytosolic factors responsible for the control of outgoing traffic from the endosomes. The main localisation and function of the low abundance phosphoinositide PI5P, that can be generated by several pathways, remains to be determined (Krauss & Haucke 2007, Leventis & Grinstein 2010, Roth 2004, Gees et al. 2010, De Matteis & Godi 2004, van Meer et al. 2008, Vicinanza et al. 2008, Lemmon 2008, Kutaleladze 2010, Robinson & Dixon 2006, Blero et al. 2007, Liu & Bankaitis 2010, McCrea & De Camilli 2009, Vicinanza et al. 2008, Di Paolo & De Camilli, 2006).

Literature Reactome attaches

Phosphoinositide-metabolizing enzymes at the interface between membrane traffic and cell signallingEMBO Rep, 2007, vol. 8, p. 241-6PubMed 17330069
The distribution and function of phosphatidylserine in cellular membranesAnnu Rev Biophys, 2010, vol. 39, p. 407-27PubMed 20192774
Phosphoinositides in constitutive membrane trafficPhysiol Rev, 2004, vol. 84, p. 699-730PubMed 15269334
The role of transient receptor potential cation channels in Ca2+ signalingCold Spring Harb Perspect Biol, 2010, vol. 2, p. a003962PubMed 20861159
PI-loting membrane trafficNat Cell Biol, 2004, vol. 6, p. 487-92PubMed 15170460
Membrane lipids: where they are and how they behaveNat Rev Mol Cell Biol, 2008, vol. 9, p. 112-24PubMed 18216768
Phosphoinositides as regulators of membrane trafficking in health and diseaseCell Mol Life Sci, 2008, vol. 65, p. 2833-41PubMed 18726176

Reactome's record lists 14 orthologous events, R-MMU-1483255 (Mus musculus), R-RNO-1483255 (Rattus norvegicus) 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"PI Metabolism". Reactome, release 97, https://reactome.org/PathwayBrowser/#/R-HSA-1483255 with StableID: R-HSA-1483255.7 (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 84 genes in this human pathway; showing 1 to 84, 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
GeneARF1	AuthorityHGNC:652	Mapping file id375 NCBI file	EvidenceTAS
GeneARF3	AuthorityHGNC:654	Mapping file id377 NCBI file	EvidenceTAS
GeneBMX	AuthorityHGNC:1079	Mapping file id660 NCBI file	EvidenceTAS
GeneENPP6	AuthorityHGNC:23409	Mapping file id133121 NCBI file	EvidenceTAS
GeneFIG4	AuthorityHGNC:16873	Mapping file id9896 NCBI file	EvidenceIEA, TAS
GeneGDE1	AuthorityHGNC:29644	Mapping file id51573 NCBI file	EvidenceTAS
GeneGDPD1	AuthorityHGNC:20883	Mapping file id284161 NCBI file	EvidenceIEA
GeneGDPD3	AuthorityHGNC:28638	Mapping file id79153 NCBI file	EvidenceIEA
GeneGDPD5	AuthorityHGNC:28804	Mapping file id81544 NCBI file	EvidenceIEA
GeneINPP4A	AuthorityHGNC:6074	Mapping file id3631 NCBI file	EvidenceTAS
GeneINPP4B	AuthorityHGNC:6075	Mapping file id8821 NCBI file	EvidenceTAS
GeneINPP5D	AuthorityHGNC:6079	Mapping file id3635 NCBI file	EvidenceTAS
GeneINPP5E	AuthorityHGNC:21474	Mapping file id56623 NCBI file	EvidenceTAS
GeneINPP5F	AuthorityHGNC:17054	Mapping file id22876 NCBI file	EvidenceTAS
GeneINPP5J	AuthorityHGNC:8956	Mapping file id27124 NCBI file	EvidenceTAS
GeneINPP5K	AuthorityHGNC:33882	Mapping file id51763 NCBI file	EvidenceTAS
GeneINPPL1	AuthorityHGNC:6080	Mapping file id3636 NCBI file	EvidenceTAS
GeneMTM1	AuthorityHGNC:7448	Mapping file id4534 NCBI file	EvidenceTAS
GeneMTMR1	AuthorityHGNC:7449	Mapping file id8776 NCBI file	EvidenceTAS
GeneMTMR10	AuthorityHGNC:25999	Mapping file id54893 NCBI file	EvidenceIEA
GeneMTMR12	AuthorityHGNC:18191	Mapping file id54545 NCBI file	EvidenceTAS
GeneMTMR14	AuthorityHGNC:26190	Mapping file id64419 NCBI file	EvidenceTAS
GeneMTMR2	AuthorityHGNC:7450	Mapping file id8898 NCBI file	EvidenceIEA, TAS
GeneMTMR3	AuthorityHGNC:7451	Mapping file id8897 NCBI file	EvidenceTAS
GeneMTMR4	AuthorityHGNC:7452	Mapping file id9110 NCBI file	EvidenceTAS
GeneMTMR6	AuthorityHGNC:7453	Mapping file id9107 NCBI file	EvidenceTAS
GeneMTMR7	AuthorityHGNC:7454	Mapping file id9108 NCBI file	EvidenceIEA, TAS
GeneMTMR8	AuthorityHGNC:16825	Mapping file id55613 NCBI file	EvidenceTAS
GeneMTMR9	AuthorityHGNC:14596	Mapping file id66036 NCBI file	EvidenceIEA, TAS
GeneOCRL	AuthorityHGNC:8108	Mapping file id4952 NCBI file	EvidenceTAS
GenePI4K2A	AuthorityHGNC:30031	Mapping file id55361 NCBI file	EvidenceTAS
GenePI4K2B	AuthorityHGNC:18215	Mapping file id55300 NCBI file	EvidenceTAS
GenePI4KA	AuthorityHGNC:8983	Mapping file id5297 NCBI file	EvidenceTAS
GenePI4KB	AuthorityHGNC:8984	Mapping file id5298 NCBI file	EvidenceTAS
GenePIK3C2A	AuthorityHGNC:8971	Mapping file id5286 NCBI file	EvidenceTAS
GenePIK3C2B	AuthorityHGNC:8972	Mapping file id5287 NCBI file	EvidenceTAS
GenePIK3C2G	AuthorityHGNC:8973	Mapping file id5288 NCBI file	EvidenceTAS
GenePIK3C3	AuthorityHGNC:8974	Mapping file id5289 NCBI file	EvidenceTAS
GenePIK3CA	AuthorityHGNC:8975	Mapping file id5290 NCBI file	EvidenceTAS
GenePIK3CB	AuthorityHGNC:8976	Mapping file id5291 NCBI file	EvidenceTAS
GenePIK3CD	AuthorityHGNC:8977	Mapping file id5293 NCBI file	EvidenceTAS
GenePIK3CG	AuthorityHGNC:8978	Mapping file id5294 NCBI file	EvidenceTAS
GenePIK3R1	AuthorityHGNC:8979	Mapping file id5295 NCBI file	EvidenceTAS
GenePIK3R2	AuthorityHGNC:8980	Mapping file id5296 NCBI file	EvidenceTAS
GenePIK3R3	AuthorityHGNC:8981	Mapping file id8503 NCBI file	EvidenceTAS
GenePIK3R4	AuthorityHGNC:8982	Mapping file id30849 NCBI file	EvidenceTAS
GenePIK3R5	AuthorityHGNC:30035	Mapping file id23533 NCBI file	EvidenceTAS
GenePIK3R6	AuthorityHGNC:27101	Mapping file id146850 NCBI file	EvidenceTAS
GenePIKFYVE	AuthorityHGNC:23785	Mapping file id200576 NCBI file	EvidenceIEA, TAS
GenePIP4K2A	AuthorityHGNC:8997	Mapping file id5305 NCBI file	EvidenceTAS
GenePIP4K2B	AuthorityHGNC:8998	Mapping file id8396 NCBI file	EvidenceTAS
GenePIP4K2C	AuthorityHGNC:23786	Mapping file id79837 NCBI file	EvidenceTAS
GenePIP4P1	AuthorityHGNC:19299	Mapping file id90809 NCBI file	EvidenceTAS
GenePIP5K1A	AuthorityHGNC:8994	Mapping file id8394 NCBI file	EvidenceTAS
GenePIP5K1B	AuthorityHGNC:8995	Mapping file id8395 NCBI file	EvidenceTAS
GenePIP5K1C	AuthorityHGNC:8996	Mapping file id23396 NCBI file	EvidenceTAS
GenePITPNB	AuthorityHGNC:9002	Mapping file id23760 NCBI file	EvidenceTAS
GenePLEKHA1	AuthorityHGNC:14335	Mapping file id59338 NCBI file	EvidenceTAS
GenePLEKHA2	AuthorityHGNC:14336	Mapping file id59339 NCBI file	EvidenceTAS
GenePLEKHA3	AuthorityHGNC:14338	Mapping file id65977 NCBI file	EvidenceTAS
GenePLEKHA4	AuthorityHGNC:14339	Mapping file id57664 NCBI file	EvidenceTAS
GenePLEKHA5	AuthorityHGNC:30036	Mapping file id54477 NCBI file	EvidenceTAS
GenePLEKHA6	AuthorityHGNC:17053	Mapping file id22874 NCBI file	EvidenceTAS
GenePLEKHA8	AuthorityHGNC:30037	Mapping file id84725 NCBI file	EvidenceTAS
GenePNPLA6	AuthorityHGNC:16268	Mapping file id10908 NCBI file	EvidenceTAS
GenePNPLA7	AuthorityHGNC:24768	Mapping file id375775 NCBI file	EvidenceIEA
GenePTEN	AuthorityHGNC:9588	Mapping file id5728 NCBI file	EvidenceTAS
GenePTPN13	AuthorityHGNC:9646	Mapping file id5783 NCBI file	EvidenceTAS
GeneRAB14	AuthorityHGNC:16524	Mapping file id51552 NCBI file	EvidenceTAS
GeneRAB4A	AuthorityHGNC:9781	Mapping file id5867 NCBI file	EvidenceTAS
GeneRAB5A	AuthorityHGNC:9783	Mapping file id5868 NCBI file	EvidenceTAS
GeneRUFY1	AuthorityHGNC:19760	Mapping file id80230 NCBI file	EvidenceTAS
GeneSACM1L	AuthorityHGNC:17059	Mapping file id22908 NCBI file	EvidenceTAS
GeneSBF1	AuthorityHGNC:10542	Mapping file id6305 NCBI file	EvidenceTAS
GeneSBF2	AuthorityHGNC:2135	Mapping file id81846 NCBI file	EvidenceIEA
GeneSYNJ1	AuthorityHGNC:11503	Mapping file id8867 NCBI file	EvidenceTAS
GeneSYNJ2	AuthorityHGNC:11504	Mapping file id8871 NCBI file	EvidenceTAS
GeneTIPE1	AuthorityHGNC:28279	Mapping file id126282 NCBI file	EvidenceTAS
GeneTIPE2	AuthorityHGNC:26277	Mapping file id79626 NCBI file	EvidenceTAS
GeneTIPE3	AuthorityHGNC:20620	Mapping file id388121 NCBI file	EvidenceTAS
GeneTNFAIP8	AuthorityHGNC:17260	Mapping file id25816 NCBI file	EvidenceTAS
GeneTPTE	AuthorityHGNC:12023	Mapping file id7179 NCBI file	EvidenceTAS
GeneTPTE2	AuthorityHGNC:17299	Mapping file id93492 NCBI file	EvidenceTAS
GeneVAC14	AuthorityHGNC:25507	Mapping file id55697 NCBI file	EvidenceIEA, TAS

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

Phospholipid metabolismR-HSA-1483257212 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.