This annexin-like domain can be found in astrotactin 2 (Astn-2), an integral membrane perforin-like protein linked to the planar cell polarity pathway in hair cells. The annexin-like domain is closest in fold to repeat three of human annexin V and similarly binds calcium, yet shares no sequence homology with it. Notably, this ASTN-2 annexin-like domain is closer in structure to human annexin repeat 3 than human annexin repeat 3 is to repeat 1. Annexin-like domains are known for their capacity to remodel membranes, triggered by calcium binding, and have also been suggested to be involved in the formation of pores in membranes both are possible biological roles of the ASTN-2 annexin-like domain [1].

1: Structure of astrotactin-2: a conserved vertebrate-specific and perforin-like membrane protein involved in neuronal development. Ni T, Harlos K, Gilbert R; Open Biol. 2016; [Epub ahead of print] PMID:27249642