This is the beta-sandwich domain found in ER membrane protein complex subunit 7 (EMC7) [1,2], which is an integral membrane component of the EMC. EMC is widely conserved and involved in membrane protein biogenesis. It mediates the insertion into endoplasmic reticulum membranes of newly synthesized membrane proteins in an energy-independent manner, both post-translational insertions of tail-anchored proteins and co-translational insertion of multipass membrane proteins [3,4]. This entry includes UPF0620 protein C83.10 from S. pombe, an orthologue of animal EMC7. This domain is also found in nodal modulators, which have been identified as part of a protein complex that participates in the nodal signalling pathway during vertebrate development [5].

1: Structural basis for membrane insertion by the human ER membrane protein complex. Pleiner T, Tomaleri GP, Januszyk K, Inglis AJ, Hazu M, Voorhees RM; Science. 2020;369:433-436. PMID:32439656

2: The architecture of EMC reveals a path for membrane protein insertion. O'Donnell JP, Phillips BP, Yagita Y, Juszkiewicz S, Wagner A, Malinverni D, Keenan RJ, Miller EA, Hegde RS; Elife. 2020; [Epub ahead of print] PMID:32459176

3: The ER membrane protein complex interacts cotranslationally to enable biogenesis of multipass membrane proteins. Shurtleff MJ, Itzhak DN, Hussmann JA, Schirle Oakdale NT, Costa EA, Jonikas M, Weibezahn J, Popova KD, Jan CH, Sinitcyn P, Vembar SS, Hernandez H, Cox J, Burlingame AL, Brodsky JL, Frost A, Borner GH, Weissman JS; Elife. 2018; [Epub ahead of print] PMID:29809151

4: EMC Is Required to Initiate Accurate Membrane Protein Topogenesis. Chitwood PJ, Juszkiewicz S, Guna A, Shao S, Hegde RS; Cell. 2018;175:1507-1519. PMID:30415835

5: Nicalin and its binding partner Nomo are novel Nodal signaling antagonists. Haffner C, Frauli M, Topp S, Irmler M, Hofmann K, Regula JT, Bally-Cuif L, Haass C; EMBO J. 2004;23:3041-3050. PMID:15257293