High impact information on LMAN2

• Furthermore, we provide evidence that internalization of VIP36, a protein that cycles between plasma membrane and Golgi, is mediated by a signal at its C-terminus that matches the internalization consensus sequence [1].
• VIP36, a novel component of glycolipid rafts and exocytic carrier vesicles in epithelial cells [2].
• We speculate that VIP36 binds to sugar residues of glycosphingolipids and/or glycosylphosphatidyl-inositol anchors and might provide a link between the extracellular/luminal face of glycolipid rafts and the cytoplasmic protein segregation machinery [2].
• The vesicular integral protein of 36 kDa (VIP36) is an intracellular animal lectin that acts as a putative cargo receptor, which recycles between the Golgi and the endoplasmic reticulum [3].
• Although it is known that VIP36 interacts with glycoproteins carrying high mannose-type oligosaccharides, detailed analyses of the sugar-binding specificity that discriminates isomeric oligosaccharide structures have not yet been performed [3].

Biological context of LMAN2

• Cycling of VIP36 is suggested by colocalisation with anterograde cargo trapped in pre-Golgi structures and modification of its N-linked carbohydrate by glycosylation enzymes of medial Golgi cisternae [4].
• In addition to the well-understood role of mannose 6-phosphate receptor in lysosomal protein sorting, the vesicular integral protein of 36 kDa (VIP36) functions as a sorting receptor by recognizing high-mannose type glycans containing alpha1-->2Man residues for transport from Golgi to the cell surface in polarized epithelial cells [5].

Anatomical context of LMAN2

• Profile-based data base scanning for animal L-type lectins and characterization of VIPL, a novel VIP36-like endoplasmic reticulum protein [6].
• Overexpressed VIP36 had been localised to the Golgi complex, plasma membrane and endocytic structures suggesting post-Golgi trafficking of this molecule (Fiedler et al., 1994) [4].
• Here we provide evidence that endogenous VIP36 is localised to the Golgi apparatus and the early secretory pathway of MDCK and Vero cells and propose that retention is easily saturated [4].

Associations of LMAN2 with chemical compounds

• VIPL is a high-mannose type I membrane glycoprotein with similar domain organization as VIP36 [6].
• Furthermore, after brefeldin A treatment VIP36 is segregated from resident Golgi proteins and codistributes with ER-Golgi recycling proteins [4].

Physical interactions of LMAN2

• The mannose lectin ERGIC-53 operates as a cargo receptor in transport of glycoproteins from ER to Golgi and the homologous lectin VIP36 may operate in quality control of glycosylation in the Golgi [7].

Regulatory relationships of LMAN2

• Sequence analysis suggests that VIPL is a ubiquitously expressed protein and appeared earlier in evolution than VIP36 [6].

Other interactions of LMAN2

• The profiles were generated from linear sequence motifs of the human L-type lectin-like membrane proteins ERGIC-53, ERGL, and VIP36 and by optimal alignment of the entire carbohydrate recognition domain of these proteins [6].

Analytical, diagnostic and therapeutic context of LMAN2

• High resolution confocal microscopy shows partial overlap of VIP36 with Golgi marker proteins [4].
• In the present study, we have analyzed, using the frontal affinity chromatography (FAC) method, the sugar-binding properties of a recombinant carbohydrate recognition domain of VIP36 (VIP36-CRD) [3].

References