Pathway Human Homo sapiens

Defensins

R-HSA-1461973 in Reactome release 97: under Antimicrobial peptides, with 54 genes placed in it by the mapping files and 2 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-1461973 (mouse), R-RNO-1461973 (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-1461973.3
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2011-12-06
Last updated: 2016-12-21
Events inside: 4, counted from the record

The defensins are a family of antimicrobial cationic peptide molecules which in mammals have a characteristic beta-sheet-rich fold and framework of six disulphide-linked cysteines (Selsted & Ouellette 2005, Ganz 2003). Human defensin peptides have two subfamilies, alpha- and beta-defensins, differing in the length of peptide chain between the six cysteines and the order of disulphide bond pairing between them. A third subfamily, the theta defensins, is derived from alpha-defensins prematurely truncated by a stop codon between the third and fourth cysteine residues. The translated products are shortened to nonapeptides, covalently dimerized by disulfide linkages, and cyclized via new peptide bonds between the first and ninth residues. Humans have one pseudogene but no translated representatives of the theta class.

In solution most alpha and beta defensins are monomers but can form dimers and higher order structures.

The primary cellular sources of defensins are neutrophils, epithelial cells and intestinal Paneth cells.Those expressed in neutrophils and the gut are predominantly constitutive, while those in epithelial tissues such as skin are often inducible by proinflammatory stimuli such as LPS or TNF-alpha.

Defensins are translated as precursor polypeptides that include a typical signal peptide or prepiece that is cleaved in the Golgi body, and a propiece, cleaved by differing mechanisms to produce the mature defensin. Mature defensin peptides can be further processed by removal of individual N-terminal residues (Yang et al. 2004). This may be a mechanism to broaden the activity profile of defensins (Ghosh et al. 2002).

Defensins have direct antimicrobial effects and kill a wide range of Gram-positive and negative bacteria, fungi and some viruses. The primary antimicrobial action of defensins is permeabilization of microbial target membranes but several additional mechanisms have been suggested (Brogden 2005, Wilmes et al. 2011). Defensins and related antimicrobial peptides such as cathelicidin bridge the innate and acquired immune responses. In addition to their antimicrobial properties, cathelicidin and several defensins show receptor-mediated chemotactic activity for immune cells such as monocytes, T cells or immature DCs, induce cytokine production by monocytes and epithelial cells, modulate angiogenesis and stimulate wound healing (Yang et al. 1999, 2000, 2004, Rehaume & Hancock 2008, Yeung et al. 2011).

Literature Reactome attaches

Primate defensinsNat Rev Microbiol, 2004, vol. 2, p. 727-38PubMed 15372083

Reactome's record lists 6 orthologous events, R-RNO-1461973 (Rattus norvegicus), R-MMU-1461973 (Mus musculus) among the species this site serves, and 4 in species this site opens no page for.

Reactome ContentService, this pathway's record · Reactome v97 · read 2026-10-01 ET · Reactome pathway browser"Defensins". Reactome, release 97, https://reactome.org/PathwayBrowser/#/R-HSA-1461973 with StableID: R-HSA-1461973.3 (accessed 2026-10-01 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 54 genes in this human pathway; showing 1 to 54, in pages of 100, sorted by symbol for reading. The order carries no ranking. 1 of the rows shown carries an id the identity file does not name, kept as the source wrote it.

Genes Reactome places in this human pathway, page 1 of 1
Gene	Authority id	Mapping file id	Evidence codes
GeneART1	AuthorityHGNC:723	Mapping file id417 NCBI file	EvidenceTAS
GeneCCR2	AuthorityHGNC:1603	Mapping file id729230 NCBI file	EvidenceTAS
GeneCCR6	AuthorityHGNC:1607	Mapping file id1235 NCBI file	EvidenceTAS
GeneCD4	AuthorityHGNC:1678	Mapping file id920 NCBI file	EvidenceTAS
GeneDEFA1	AuthorityHGNC:2761	Mapping file id1667 NCBI file	EvidenceTAS
GeneDEFA1B	AuthorityHGNC:33596	Mapping file id728358 NCBI file	EvidenceTAS
GeneDEFA3	AuthorityHGNC:2762	Mapping file id1668 NCBI file	EvidenceTAS
GeneDEFA4	AuthorityHGNC:2763	Mapping file id1669 NCBI file	EvidenceTAS
GeneDEFA5	AuthorityHGNC:2764	Mapping file id1670 NCBI file	EvidenceTAS
GeneDEFA6	AuthorityHGNC:2765	Mapping file id1671 NCBI file	EvidenceTAS
GeneDEFB1	AuthorityHGNC:2766	Mapping file id1672 NCBI file	EvidenceTAS
GeneDEFB103A	AuthorityHGNC:15967	Mapping file id414325 NCBI file	EvidenceTAS
GeneDEFB103B	AuthorityHGNC:31702	Mapping file id55894 NCBI file	EvidenceTAS
GeneDEFB104A	AuthorityHGNC:18115	Mapping file id140596 NCBI file	EvidenceTAS
GeneDEFB104B	AuthorityHGNC:26165	Mapping file id503618 NCBI file	EvidenceTAS
GeneDEFB105A	AuthorityHGNC:18087	Mapping file id245908 NCBI file	EvidenceTAS
GeneDEFB105B	AuthorityHGNC:29930	Mapping file id504180 NCBI file	EvidenceTAS
GeneDEFB106A	AuthorityHGNC:18088	Mapping file id245909 NCBI file	EvidenceTAS
GeneDEFB106B	AuthorityHGNC:28879	Mapping file id503841 NCBI file	EvidenceTAS
GeneDEFB107A	AuthorityHGNC:18086	Mapping file id245910 NCBI file	EvidenceTAS
GeneDEFB107B	AuthorityHGNC:31918	Mapping file id503614 NCBI file	EvidenceTAS
GeneDEFB108B	AuthorityHGNC:29966	Mapping file id245911 NCBI file	EvidenceTAS
GeneDEFB109B	AuthorityHGNC:33469	Mapping file id641517 NCBI file	EvidenceTAS
GeneDEFB110	AuthorityHGNC:18091	Mapping file id245913 NCBI file	EvidenceTAS
GeneDEFB112	AuthorityHGNC:18093	Mapping file idENSG00000180872 Ensembl file	EvidenceTAS
GeneDEFB113	AuthorityHGNC:18094	Mapping file id245927 NCBI file	EvidenceTAS
GeneDEFB114	AuthorityHGNC:18095	Mapping file id245928 NCBI file	EvidenceTAS
GeneDEFB115	AuthorityHGNC:18096	Mapping file id245929 NCBI file	EvidenceTAS
GeneDEFB116	AuthorityHGNC:18097	Mapping file id245930 NCBI file	EvidenceTAS
GeneDEFB118	AuthorityHGNC:16196	Mapping file id117285 NCBI file	EvidenceTAS
GeneDEFB119	AuthorityHGNC:18099	Mapping file id245932 NCBI file	EvidenceTAS
GeneDEFB121	AuthorityHGNC:18101	Mapping file id245934 NCBI file	EvidenceTAS
GeneDEFB123	AuthorityHGNC:18103	Mapping file id245936 NCBI file	EvidenceTAS
GeneDEFB124	AuthorityHGNC:18104	Mapping file id245937 NCBI file	EvidenceTAS
GeneDEFB125	AuthorityHGNC:18105	Mapping file id245938 NCBI file	EvidenceTAS
GeneDEFB126	AuthorityHGNC:15900	Mapping file id81623 NCBI file	EvidenceTAS
GeneDEFB127	AuthorityHGNC:16206	Mapping file id140850 NCBI file	EvidenceTAS
GeneDEFB128	AuthorityHGNC:18106	Mapping file id245939 NCBI file	EvidenceTAS
GeneDEFB129	AuthorityHGNC:16218	Mapping file id140881 NCBI file	EvidenceTAS
GeneDEFB130A	AuthorityHGNC:18107	Mapping file id245940 NCBI file	EvidenceTAS
GeneDEFB130B	AuthorityHGNC:39814	Mapping file id100133267 NCBI file	EvidenceTAS
GeneDEFB131A	AuthorityHGNC:18108	Mapping file id644414 NCBI file	EvidenceTAS
GeneDEFB132	AuthorityHGNC:33806	Mapping file id400830 NCBI file	EvidenceTAS
GeneDEFB133	AuthorityHGNC:31331	Mapping file idENSG00000214643 Ensembl file	EvidenceTAS
GeneDEFB134	AuthorityHGNC:32399	Mapping file id613211 NCBI file	EvidenceTAS
GeneDEFB135	AuthorityHGNC:32400	Mapping file id613209 NCBI file	EvidenceTAS
GeneDEFB136	AuthorityHGNC:34433	Mapping file id613210 NCBI file	EvidenceTAS
GeneDEFB4A	AuthorityHGNC:2767	Mapping file id1673 NCBI file	EvidenceTAS
GeneDEFB4B	AuthorityHGNC:30193	Mapping file id100289462 NCBI file	EvidenceTAS
GenePRSS2	AuthorityHGNC:9483	Mapping file id5645 NCBI file	EvidenceTAS
GenePRSS3	AuthorityHGNC:9486	Mapping file id5646 NCBI file	EvidenceTAS
GeneTLR1	AuthorityHGNC:11847	Mapping file id7096 NCBI file	EvidenceTAS
GeneTLR2	AuthorityHGNC:11848	Mapping file id7097 NCBI file	EvidenceTAS
Geneno symbol in the identity file	Authoritynone	Mapping file id155971 NCBI file	EvidenceTAS

Evidence codes on this page: 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

Antimicrobial peptidesR-HSA-6803157101 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.