InterPro domain: IPR005052

Lectins are structurally diverse proteins that bind to specific carbohydrates. This family includes the VIP36 and ERGIC-53 lectins. These two proteins were the first members of the family of animal lectins similar to the leguminous plant lectins [ 1 ]. The alignment for this family is towards the N terminus, where the similarity of VIP36 and ERGIC-53 is greatest. Although they have been identified as a family of animal lectins, this alignment also includes yeast sequences[ 2 ].

ERGIC-53 is a 53kDa protein, localised to the intermediate region between the endoplasmic reticulum and the Golgi apparatus (ER-Golgi-Intermediate Compartment, ERGIC). It was identified as a calcium-dependent, mannose-specific lectin [ 2 ]. Its dysfunction has been associated with combined factors V and VIII deficiency, suggesting an important and substrate-specific role for ERGIC-53 in the glycoprotein-secreting pathway [ 3 , 3 ].

The L-type lectin-like domain has an overall globular shape composed of a beta-sandwich of two major twisted antiparallel beta-sheets. The beta-sandwich comprises a major concave beta-sheet and a minor convex beta-sheet, in a variation of the jelly roll fold [ 4 , 5 , 6 , 7 ].

1. A putative novel class of animal lectins in the secretory pathway homologous to leguminous lectins. Cell 77, 625-6
2. ERGIC-53 is a functional mannose-selective and calcium-dependent human homologue of leguminous lectins. Mol. Biol. Cell 7, 483-93
3. ERGIC-53 gene structure and mutation analysis in 19 combined factors V and VIII deficiency families. Blood 93, 2261-6
4. Crystal structure of the carbohydrate recognition domain of p58/ERGIC-53, a protein involved in glycoprotein export from the endoplasmic reticulum. J. Biol. Chem. 277, 15979-84
5. The crystal structure of the carbohydrate-recognition domain of the glycoprotein sorting receptor p58/ERGIC-53 reveals an unpredicted metal-binding site and conformational changes associated with calcium ion binding. J. Mol. Biol. 334, 845-51
6. Structures of the carbohydrate recognition domain of Ca2+-independent cargo receptors Emp46p and Emp47p. J. Biol. Chem. 281, 10410-9
7. Structural basis for recognition of high mannose type glycoproteins by mammalian transport lectin VIP36. J. Biol. Chem. 282, 28246-55