This domain was first identified as a zinc finger at the C terminus of AN1 SWISSPROT, a ubiquitin-like protein in Xenopus laevis.

[2] For example, the human protein Znf216 has an A20 zinc-finger at the N terminus and an AN1 zinc-finger at the C terminus, acting to negatively regulate the NFkappaB activation pathway and to interact with components of the immune response like RIP, IKKgamma and TRAF6.

[1] Proteins containing an AN1-type zinc finger include: AN1-type zinc finger domains are widely present across diverse "Euryarchaeota" and Nitrososphaerota, where they are often fused to membrane-associated peptidase domains such as the rhomboid family serine peptidase, transglutaminase-like thiol peptidases of the papain fold, and Zn-dependent metallopeptidases.

These fusions suggest membrane-associated roles for AN1 domain containing proteins in archaea, such as in the proteolytic processing of polypeptides and in regulating protein folding or stability.

The architectural syntax is remarkably similar to that of the prokaryotic B-box zinc finger and LIM domains.