The L27 domain is a protein interaction module that exists in a large family of scaffold proteins, functioning as an organisation centre of large protein assemblies required for the establishment and maintenance of cell polarity. L27 domains form specific heterotetrameric complexes, in which each domain contains three alpha-helices [1].

1: The tetrameric L27 domain complex as an organization platform for supramolecular assemblies. Feng W, Long JF, Fan JS, Suetake T, Zhang M; Nat Struct Mol Biol. 2004;11:475-480. PMID:15048107

2: The stardust family protein MPP7 forms a tripartite complex with LIN7 and DLG1 that regulates the stability and localization of DLG1 to cell junctions. Bohl J, Brimer N, Lyons C, Vande Pol SB; J Biol Chem. 2007;282:9392-9400. PMID:17237226