Pathway Human Homo sapiens

Collagen degradation

R-HSA-1442490 in Reactome release 97: under Degradation of the extracellular matrix, with 64 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-1442490 (mouse), R-RNO-1442490 (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-1442490.5
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2012-12-04
Last updated: 2020-03-16
Events inside: 34, counted from the record

Collagen fibril diameter and spatial organisation are dependent on the species, tissue type and stage of development (Parry 1988). The lengths of collagen fibrils in mature tissues are largely unknown but in tendon can be measured in millimetres (Craig et al. 1989). Collagen fibrils isolated from adult bovine corneal stroma had ~350 collagen molecules in transverse section, tapering down to three molecules at the growing tip (Holmes & Kadler 2005).

The classical view of collagenases is that they actively unwind the triple helical chain, a process termed molecular tectonics (Overall 2002, Bode & Maskos 2003), before preferentially cleaving the alpha2 chain followed by the remaining chains (Chung et al. 2004). More recently it has been suggested that collagen fibrils exist in an equilibrium between protected and vulnerable states (Stultz 2002, Nerenberg & Stultz 2008). The prototypical triple-helical structure of collagen does not fit into the active site of collagenase MMPs. In addition the scissile bonds are not solvent-exposed and are therefore inaccessible to the collagenase active site (Chung et al. 2004, Stultz 2002). It was realized that collagen must locally unfold into non-triple helical regions to allow collagenolysis. Observations using circular dichroism and differential scanning calorimetry confirm that there is considerable heterogeneity along collagen fibres (Makareeva et al. 2008) allowing access for MMPs at physiological temperatures (Salsas-Escat et al. 2010).

Collagen fibrils with cut chains are unstable and accessible to proteinases that cannot cleave intact collagen strands (Woessner & Nagase 2000, Somerville et al. 2003). Continued degradation leads to the formation of gelatin (Lovejoy et al. 1999). Degradation of collagen types other than I-III is less well characterized but believed to occur in a similar manner.

Metalloproteinases (MMPs) play a major part in the degradation of several extracellular macromolecules including collagens. MMP1 (Welgus et al. 1981), MMP8 (Hasty et al. 1987), and MMP13 (Knauper et al. 1996), sometimes referred to as collagenases I, II and III respectively, are able to initiate the intrahelical cleavage of the major fibril forming collagens I, II and III at neutral pH, and thus thought to define the rate-limiting step in normal tissue remodeling events. All can cleave additional substrates including other collagen subtypes. Collagenases cut collagen alpha chains at a single conserved Gly-Ile/Leu site approximately 3/4 of the molecule's length from the N-terminus (Fields 1991, Chung et al. 2004). The cleavage site is characterised by the motif G(I/L)(A/L); the G-I/L bond is cleaved. In collagen type I this corresponds to G953-I954 in the Uniprot canonical alpha chain sequences (often given as G775-I776 in literature). It is not clear why only this bond is cleaved, as the motif occurs at several other places in the chain. MMP14, a membrane-associated MMP also known as Membrane-type matrix metalloproteinase 1 (MT-MMP1), is able to cleave collagen types I, II and III (Ohuchi et al. 1997).

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 64 genes in this human pathway; showing 1 to 64, 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
GeneADAM10	AuthorityHGNC:188	Mapping file id102 NCBI file	EvidenceIEA
GeneADAM17	AuthorityHGNC:195	Mapping file id6868 NCBI file	EvidenceIEA
GeneADAM9	AuthorityHGNC:216	Mapping file id8754 NCBI file	EvidenceIEA
GeneCOL10A1	AuthorityHGNC:2185	Mapping file id1300 NCBI file	EvidenceIEA, TAS
GeneCOL11A1	AuthorityHGNC:2186	Mapping file id1301 NCBI file	EvidenceIEA, TAS
GeneCOL11A2	AuthorityHGNC:2187	Mapping file id1302 NCBI file	EvidenceIEA, TAS
GeneCOL12A1	AuthorityHGNC:2188	Mapping file id1303 NCBI file	EvidenceTAS
GeneCOL13A1	AuthorityHGNC:2190	Mapping file id1305 NCBI file	EvidenceTAS
GeneCOL14A1	AuthorityHGNC:2191	Mapping file id7373 NCBI file	EvidenceIEA
GeneCOL15A1	AuthorityHGNC:2192	Mapping file id1306 NCBI file	EvidenceTAS
GeneCOL16A1	AuthorityHGNC:2193	Mapping file id1307 NCBI file	EvidenceIEA
GeneCOL17A1	AuthorityHGNC:2194	Mapping file id1308 NCBI file	EvidenceIEA
GeneCOL18A1	AuthorityHGNC:2195	Mapping file id80781 NCBI file	EvidenceTAS
GeneCOL19A1	AuthorityHGNC:2196	Mapping file id1310 NCBI file	EvidenceTAS
GeneCOL1A1	AuthorityHGNC:2197	Mapping file id1277 NCBI file	EvidenceIEA, TAS
GeneCOL1A2	AuthorityHGNC:2198	Mapping file id1278 NCBI file	EvidenceIEA, TAS
GeneCOL23A1	AuthorityHGNC:22990	Mapping file id91522 NCBI file	EvidenceIEA
GeneCOL25A1	AuthorityHGNC:18603	Mapping file id84570 NCBI file	EvidenceTAS
GeneCOL26A1	AuthorityHGNC:18038	Mapping file id136227 NCBI file	EvidenceTAS
GeneCOL2A1	AuthorityHGNC:2200	Mapping file id1280 NCBI file	EvidenceIEA, TAS
GeneCOL3A1	AuthorityHGNC:2201	Mapping file id1281 NCBI file	EvidenceIEA, TAS
GeneCOL4A1	AuthorityHGNC:2202	Mapping file id1282 NCBI file	EvidenceIEA, TAS
GeneCOL4A2	AuthorityHGNC:2203	Mapping file id1284 NCBI file	EvidenceIEA, TAS
GeneCOL4A3	AuthorityHGNC:2204	Mapping file id1285 NCBI file	EvidenceIEA, TAS
GeneCOL4A4	AuthorityHGNC:2206	Mapping file id1286 NCBI file	EvidenceIEA, TAS
GeneCOL4A5	AuthorityHGNC:2207	Mapping file id1287 NCBI file	EvidenceIEA, TAS
GeneCOL4A6	AuthorityHGNC:2208	Mapping file id1288 NCBI file	EvidenceIEA, TAS
GeneCOL5A1	AuthorityHGNC:2209	Mapping file id1289 NCBI file	EvidenceTAS
GeneCOL5A2	AuthorityHGNC:2210	Mapping file id1290 NCBI file	EvidenceTAS
GeneCOL5A3	AuthorityHGNC:14864	Mapping file id50509 NCBI file	EvidenceTAS
GeneCOL6A1	AuthorityHGNC:2211	Mapping file id1291 NCBI file	EvidenceTAS
GeneCOL6A2	AuthorityHGNC:2212	Mapping file id1292 NCBI file	EvidenceTAS
GeneCOL6A3	AuthorityHGNC:2213	Mapping file id1293 NCBI file	EvidenceTAS
GeneCOL6A5	AuthorityHGNC:26674	Mapping file id256076 NCBI file	EvidenceTAS
GeneCOL6A6	AuthorityHGNC:27023	Mapping file id131873 NCBI file	EvidenceTAS
GeneCOL7A1	AuthorityHGNC:2214	Mapping file id1294 NCBI file	EvidenceIEA, TAS
GeneCOL8A1	AuthorityHGNC:2215	Mapping file id1295 NCBI file	EvidenceIEA, TAS
GeneCOL8A2	AuthorityHGNC:2216	Mapping file id1296 NCBI file	EvidenceIEA, TAS
GeneCOL9A1	AuthorityHGNC:2217	Mapping file id1297 NCBI file	EvidenceIEA
GeneCOL9A2	AuthorityHGNC:2218	Mapping file id1298 NCBI file	EvidenceIEA
GeneCOL9A3	AuthorityHGNC:2219	Mapping file id1299 NCBI file	EvidenceIEA
GeneCTSB	AuthorityHGNC:2527	Mapping file id1508 NCBI file	EvidenceTAS
GeneCTSD	AuthorityHGNC:2529	Mapping file id1509 NCBI file	EvidenceTAS
GeneCTSK	AuthorityHGNC:2536	Mapping file id1513 NCBI file	EvidenceTAS
GeneCTSL	AuthorityHGNC:2537	Mapping file id1514 NCBI file	EvidenceTAS
GeneELANE	AuthorityHGNC:3309	Mapping file id1991 NCBI file	EvidenceIEA
GeneFURIN	AuthorityHGNC:8568	Mapping file id5045 NCBI file	EvidenceIEA, TAS
GeneMMP1	AuthorityHGNC:7155	Mapping file id4312 NCBI file	EvidenceIEA, TAS
GeneMMP10	AuthorityHGNC:7156	Mapping file id4319 NCBI file	EvidenceIEA, TAS
GeneMMP11	AuthorityHGNC:7157	Mapping file id4320 NCBI file	EvidenceTAS
GeneMMP12	AuthorityHGNC:7158	Mapping file id4321 NCBI file	EvidenceTAS
GeneMMP13	AuthorityHGNC:7159	Mapping file id4322 NCBI file	EvidenceIEA, TAS
GeneMMP14	AuthorityHGNC:7160	Mapping file id4323 NCBI file	EvidenceIEA, TAS
GeneMMP15	AuthorityHGNC:7161	Mapping file id4324 NCBI file	EvidenceTAS
GeneMMP19	AuthorityHGNC:7165	Mapping file id4327 NCBI file	EvidenceIEA
GeneMMP2	AuthorityHGNC:7166	Mapping file id4313 NCBI file	EvidenceIEA, TAS
GeneMMP20	AuthorityHGNC:7167	Mapping file id9313 NCBI file	EvidenceTAS
GeneMMP3	AuthorityHGNC:7173	Mapping file id4314 NCBI file	EvidenceIEA, TAS
GeneMMP7	AuthorityHGNC:7174	Mapping file id4316 NCBI file	EvidenceTAS
GeneMMP8	AuthorityHGNC:7175	Mapping file id4317 NCBI file	EvidenceTAS
GeneMMP9	AuthorityHGNC:7176	Mapping file id4318 NCBI file	EvidenceIEA, TAS
GenePHYKPL	AuthorityHGNC:28249	Mapping file id85007 NCBI file	EvidenceTAS
GenePRSS2	AuthorityHGNC:9483	Mapping file id5645 NCBI file	EvidenceTAS
GeneTMPRSS6	AuthorityHGNC:16517	Mapping file id164656 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

Degradation of the extracellular matrixR-HSA-1474228140 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.