9.B.417.  The MCFD2/LMAN1 Complex Receptor (MLM-CR) Family 

LMAN ( a mannose-specific lectin, Ergic-53; 510 aas with two TMSs, N- and C-terminal) and MCFD2 of 146 aas and one N-terminal TMS, form a complex that recognizes sugar residues of glycoproteins, glycolipids, or glycosylphosphatidyl inositol anchors, It may be involved in the sorting and/or recycling of proteins, lipids, or both. The LMAN1-MCFD2 complex forms a specific cargo receptor for the ER-to-Golgi transport of selected proteins (Nufer et al. 2003; Zhang et al. 2003). It plays a role in the secretion of coagulation factors. A 1.60 Å resolution crystal structure of the ERGIC-53(CRD)-MCFD2 complex is available showing that MCFD2, but not ERGIC-53-CRD, exhibits conformational plasticity that may be relevant to its accommodation of various polypeptide ligands (Satoh et al. 2020). The LMAN1-MCFD2 complex is a cargo receptor for the ER-Golgi transport of alpha1-antitrypsin (Zhang et al. 2022).