Mannose-specific lectin. May recognize sugar residues of glycoproteins, glycolipids, or glycosylphosphatidyl inositol anchors and may be involved in the sorting 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 (By similarity). Exists both as a covalent disulfide-linked homohexamer, and a complex of three disulfide-linked dimers non-covalently kept together. Interacts with MCFD2. May interact with TMEM115. Interacts with RAB3GAP1 and RAB3GAP2. Interacts with UBXN6. Interacts with SERPINA1/alpha1-antitrypsin (By similarity). The FF ER export motif at the C-terminus is not sufficient to support endoplasmic reticulum exit, and needs assistance of Gln-508 for proper recognition of COPII coat components.