SPAG11B:Sperm-associated antigen 11B

Gene Name
Sperm-associated antigen 11B
Protein ID
Chromosome ID
HPP Status
Protein Name
Sperm-associated antigen 11B


sperm associated antigen 11B





human epididymis-specific protein 2

epididymal protein 2B


"epididymal protein 2B"

Human epididymis-specific protein 2



Protein EP2

sperm-associated antigen 11B

sperm antigen HE2

Sperm antigen HE2

[Reference: ]
Chromosomal Position
8p23.1 | Start:7442684 End:7442684

Entrez Gene Summary for SPAG11B
This gene encodes several androgen-dependent, epididymis-specific secretory proteins. The specific functions of these proteins have not been determined, but they are thought to be involved in sperm maturation. Some of the isoforms contain regions of similarity to beta-defensins, a family of antimicrobial peptides. The gene is located on chromosome 8p23 near the defensin gene cluster. Alternative splicing of this gene results in seven transcript variants encoding different isoforms. Two different N-terminal and five different C-terminal protein sequences are encoded by the splice variants. Two additional variants have been described, but their full length sequences have not been determined. (provided by RefSeq, Jul 2008)

[Reference: ]
External IDs
Hgnc ID: 14534 EntrezGene ID: 10407 Ensembl ID: ENSG00000164871
[Reference: ]
Reference Source

Gene Reference Into Function (GeneRIF)

PubMed IDGeneRIF TextLast Update
10819450In the chimpanzee epididymis, several mRNA HE2/EP2 variants are produced. Of these, three cDNAs code for two different protein sequences that have a cysteine distribution characteristic for beta-defensins.2001-04-26
11259252The human HE2/EP2 gene is the fusion product of two ancestral beta-defensin genes. During its evolution, the gene has acquired additional exons whose inclusion produces new message variants that encode peptides unrelated to defensins.2001-04-26
12193388HE2 peptides were detected in human epididymal epithelium, epididymal fluid, and ejaculate2010-01-21
14662784HE2 transcriptional and translational products normally expressed in the caput epididymidis were not affected by vasectomy.2010-01-21
15229135EP2 expression is more widespread in male reproductive tract than realized previously. Activity of every EP2 variant tested is antibacterial. Further investigation may reveal additional roles for EP2 peptides in primate male reproductive tract.2010-01-21
16411022Isoform C of SPAG11B encodes a peptide with antimicrobial activity against E. coli.2014-11-19
19535787SPAG11B/D is both a substrate and a potent inhibitor of TPSAB1 activity.2010-01-21
21933954Combination of two proteins, SPAG11B and TEX101, can be used for differential diagnosis of azoospermia2012-04-07
25573789we report the three dimensional structure of the human SPAG11B proteins and their C-terminal peptides. web-based hydropathy, amphipathicity, and topology (WHAT) analyses and grand average of hydropathy2015-12-12


Relevant citations within the PubMed literature


Putative/known Functions


Homologues, Orthologues, Paralogues and Family

Sequence Similarity and Functional Annotation

Sequence Similarity

Db NameQuery UniSubject UniSequence LengthAlignment LengthIdentityCoverageMismatchesGap OpeningsQuery StartQuery EndSubject StartSubject EndEvalueBit Score
Reviewed non-human mammalianSG11B_HUMANSPG11_PANTR10310397.0910030110311031E-53205
Islam MT, Garg G, Hancock WS, Risk BA, Baker MS, Ranganathan S (2014) Protannotator: A Semiautomated Pipeline for Chromosome-Wise Functional Annotation of the "Missing" Human Proteome. J Proteome Res. 13, 76-83.

InterProScan Annotation

Uniprot IDInterpro IDGo IDTypeNameCategoryDescription
SG11B_HUMANIPR007988GO:0005576FamilySperm antigen HE2Cellular Componentextracellular region
Islam MT, Garg G, Hancock WS, Risk BA, Baker MS, Ranganathan S (2014) Protannotator: A Semiautomated Pipeline for Chromosome-Wise Functional Annotation of the "Missing" Human Proteome. J Proteome Res. 13, 76-83.

Post Translational Modifications

Protein Protein Interactions

Best Available Mass Spectra without FDR


Evidence File
Fenyö, David; Beavis, Ronald C. (2015). "The GPMDB REST interface". Bioinformatics 31 (12): 2056–2058. doi:10.1093/bioinformatics/btv107. ISSN 1367-4803. ">Global Proteome Machine Database - THE GPM


Peptide SequenceScoresPride IDSpectrum IDAnnotation
No results found.
Evidence File
Vizcaino JA, et al. 2016 update of the PRIDE database and related tools. Nucleic Acids Res. 2016 Jan 1;44(D1):D447-D456. ">PRIDE Archive

Proteomics DB

Evidence File
Wilhelm, M et al. (2014) Mass-spectrometry-based draft of the human proteome. Nature. 509:582-7. ">Proteomics DB