Pathway Human Homo sapiens

Triglyceride catabolism

R-HSA-163560 in Reactome release 97: under Triglyceride metabolism, with 24 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-163560 (mouse), R-RNO-163560 (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-163560.5
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2005-04-11
Last updated: 2017-04-20
Events inside: 17, counted from the record
Also named: Hormone-sensitive lipase (HSL)-mediated triacylglycerol hydrolysis

Triacylglycerol is a major energy store in the body and its hydrolysis to yield fatty acids and glycerol is a tightly regulated part of energy metabolism. A central part in this regulation is played by hormone-sensitive lipase (HSL), a neutral lipase abundant in adipocytes and skeletal and cardiac muscle, but also abundant in ovarian and adrenal tissue, where it mediates cholesterol ester hydrolysis, yielding cholesterol for steroid biosynthesis. The hormones to which it is sensitive include catecholamines (e.g., epinephrine), ACTH, and glucagon, all of which trigger signaling cascades that lead to its phosphorylation and activation, and insulin, which sets off events leading to its dephosphorylation and inactivation (Holm et al. 2000; Kraemer and Shen 2002).

The processes of triacylglycerol and cholesterol ester hydrolysis are also regulated by subcellular compartmentalization: these lipids are packaged in cytosolic particles and the enzymes responsible for their hydrolysis, and perhaps for additional steps in their metabolism, are organized at the surfaces of these particles (e.g., Brasaemle et al. 2004). This organization is dynamic: the inactive form of HSL is not associated with the particles, but is translocated there after being phosphorylated. Conversely, perilipin, a major constituent of the particle surface, appears to block access of enzymes to the lipids within the particle; its phosphorylation allows greater access.

Here, HSL-mediated triacylglycerol hydrolysis is described as a pathway containing twelve reactions. The first six of these involve activation: phosphorylation of HSL, dimerization of HSL, disruption of CGI-58:perilipin complexes at the surfaces of cytosolic lipid particles, phosphorylation of perilipin, association of phosphorylated HSL with FABP, and translocation of HSL from the cytosol to the surfaces of lipid particles. The next four reactions are the hydrolysis reactions themselves: the hydrolysis of cholesterol esters, and the successive removal of three fatty acids from triacylglycerol. The last two reactions, dephosphorylation of perilipin and HSL, negatively regulate the pathway. These events are outlined in the figure below. Inputs (substrates) and outputs (products) of individual reactions are connected by black arrows; blue lines connect output activated enzymes to the other reactions that they catalyze.

Despite the undoubted importance of these reactions in normal human energy metabolism and in the pathology of diseases such as type II diabetes, they have been studied only to a limited extent in human cells and tissues. Most experimental data are derived instead from two rodent model systems: primary adipocytes from rats, and mouse 3T3-L1 cells induced to differentiate into adipocytes.

Literature Reactome attaches

Molecular mechanisms regulating hormone-sensitive lipase and lipolysisAnnu Rev Nutr, 2000, vol. 20, p. 365-93PubMed 10940339
Hormone-sensitive lipase: control of intracellular tri-(di-)acylglycerol and cholesteryl ester hydrolysisJ Lipid Res, 2002, vol. 43, p. 1585-94PubMed 12364542

Reactome's record lists 14 orthologous events, R-RNO-163560 (Rattus norvegicus), R-MMU-163560 (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 2026-09-29 ET · Reactome pathway browser"Triglyceride catabolism". Reactome, release 97, https://reactome.org/PathwayBrowser/#/R-HSA-163560 with StableID: R-HSA-163560.5 (accessed 2026-09-29 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 24 genes in this human pathway; showing 1 to 24, 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
GeneABHD5	AuthorityHGNC:21396	Mapping file id51099 NCBI file	EvidenceIEA
GeneCAV1	AuthorityHGNC:1527	Mapping file id857 NCBI file	EvidenceIEA
GeneFABP1	AuthorityHGNC:3555	Mapping file id2168 NCBI file	EvidenceTAS
GeneFABP12	AuthorityHGNC:34524	Mapping file id646486 NCBI file	EvidenceTAS
GeneFABP2	AuthorityHGNC:3556	Mapping file id2169 NCBI file	EvidenceTAS
GeneFABP3	AuthorityHGNC:3557	Mapping file id2170 NCBI file	EvidenceTAS
GeneFABP4	AuthorityHGNC:3559	Mapping file id2167 NCBI file	EvidenceIEA, TAS
GeneFABP5	AuthorityHGNC:3560	Mapping file id2171 NCBI file	EvidenceTAS
GeneFABP6	AuthorityHGNC:3561	Mapping file id2172 NCBI file	EvidenceTAS
GeneFABP7	AuthorityHGNC:3562	Mapping file id2173 NCBI file	EvidenceTAS
GeneFABP9	AuthorityHGNC:3563	Mapping file id646480 NCBI file	EvidenceTAS
GeneGPD2	AuthorityHGNC:4456	Mapping file id2820 NCBI file	EvidenceTAS
GeneLIPE	AuthorityHGNC:6621	Mapping file id3991 NCBI file	EvidenceIEA
GeneMGLL	AuthorityHGNC:17038	Mapping file id11343 NCBI file	EvidenceIEA
GenePLIN1	AuthorityHGNC:9076	Mapping file id5346 NCBI file	EvidenceIEA
GenePLIN3	AuthorityHGNC:16893	Mapping file id10226 NCBI file	EvidenceTAS
GenePNPLA4	AuthorityHGNC:24887	Mapping file id8228 NCBI file	EvidenceTAS
GenePNPLA5	AuthorityHGNC:24888	Mapping file id150379 NCBI file	EvidenceTAS
GenePPP1CA	AuthorityHGNC:9281	Mapping file id5499 NCBI file	EvidenceIEA
GenePPP1CB	AuthorityHGNC:9282	Mapping file id5500 NCBI file	EvidenceIEA
GenePPP1CC	AuthorityHGNC:9283	Mapping file id5501 NCBI file	EvidenceIEA
GenePRKACA	AuthorityHGNC:9380	Mapping file id5566 NCBI file	EvidenceIEA
GenePRKACB	AuthorityHGNC:9381	Mapping file id5567 NCBI file	EvidenceIEA
GenePRKACG	AuthorityHGNC:9382	Mapping file id5568 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

Triglyceride metabolismR-HSA-897922738 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.