ADAM20

Disintegrin and metalloproteinase domain-containing protein 20 is an enzyme encoded by the ADAM20 gene in humans. It is a membrane disintegrin-metalloprotease that belongs to the ADAM family. It is exclusively expressed in the Testes and is similar to sperm cell-specific fertilins -alpha and -beta.

ADAM20
Identifiers
Aliases	ADAM20, ADAM metallopeptidase domain 20
External IDs	OMIM: 603712; MGI: 3045694; HomoloGene: 128364; GeneCards: ADAM20; OMA:ADAM20 - orthologs
Gene location (Human) Chr. Chromosome 14 (human)[1] Band 14q24.2 Start 70,522,358 bp[1] End 70,535,015 bp[1]
Gene location (Mouse) Chr. Chromosome 8 (mouse)[2] Band 8|8 A4 Start 41,276,027 bp[2] End 41,280,074 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in sperm gonad testicle right testis left testis buccal mucosa cell Achilles tendon corpus callosum muscle of thigh cervix Top expressed in spermatid testicle spermatocyte pancreas islet of Langerhans primary visual cortex More reference expression data BioGPS n/a
Gene ontology Molecular function peptidase activity metalloendopeptidase activity hydrolase activity metallopeptidase activity metal ion binding Cellular component integral component of membrane plasma membrane membrane Biological process proteolysis single fertilization binding of sperm to zona pellucida Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 8748 546055 Ensembl ENSG00000134007 ENSMUSG00000054033 UniProt O43506 Q7M762 RefSeq (mRNA) NM_003814 NM_001025380 RefSeq (protein) NP_003805 NP_001020551 Location (UCSC) Chr 14: 70.52 – 70.54 Mb Chr 8: 41.28 – 41.28 Mb PubMed search [3] [4]
Wikidata
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Its cDNA is tightly linked to marker SHGC-36001 on chromosome 14q24.1. ADAM20 is related to fertilin α (ADAM1A/B pseudogene), fertilin β (ADAM2), and fertilin γ (ADAM9). In humans, fertilin α has recently been deactivated so that ADAM20 may be the functional equivalent of fertilin α in humans.^[5]

Structure

Computed structure of the ADAM 20 protein.^[6] The signal and propeptide sites have been removed as they would be cleaved in the active form. Extracellular domains are highlighted in red, helical domains are in yellow, and cytoplasmic domains are in blue.

In common with other ADAM family members, ADAM20 contains a N-terminal reprolysin family propeptide (residues 57–159), reprolysin (M12B) family zinc metalloprotease domain (207–395), disintegrin domain (416–488), and a C-terminal ADAM cysteine-rich domain (493–605).^[7]

The propeptide acts as a signal peptide and an activator domain. This prodomain has a cysteine that interacts with a zinc in the catalytic domain, thereby preventing the catalytic activity of the protein. When the pro-protein domain is cleaved, this cysteine zinc bond is broken, and the protein is activated.^[8] A notable variant showed an amino acid difference in the pro protein domain that prevented the cleavage of this domain, which prevented the fusion of the sperm cell to an egg.^[9]