Characterization of VIP36, an animal lectin homologous to leguminous lectins.
VIP36 was isolated from MDCK cells as a component of glycolipid-enriched detergent-insoluble complexes. The protein is localized to the Golgi apparatus and the cell surface, and belongs to a new family of legume lectin homologues in the animal secretory pathway that might be involved in the trafficking of glycoproteins, glycolipids or both. Here we show that VIP36 is N-glycosylated and expressed in organs abundant in epithelial cells as well as in non-epithelial organs. Our studies demonstrate that the recombinant exoplasmic/luminal domain of VIP36 binds Ca2+ and that the protein decorates internal membrane structures of MDCK cells in vitro that are distinct from the Golgi apparatus. This binding requires Ca2+ and can be specifically inhibited by N-acetyl-D-galactosamine. The recombinant protein was used for affinity chromatography. Glycopeptides obtained from [3H]galactose-labelled cells bind to VIP36 and can be eluted with N-acetyl-D-galactosamine. Our data imply that VIP36 functions as a lectin in post-Golgi trafficking.
Fiedler
K
K
Cell Biology Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
Simons
K
K
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D004847:Epithelial Cells; D007887:Fabaceae / Q000737:chemistry; D006031:Glycosylation; D037102:Lectins; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D037121:Plant Lectins; D010946:Plants, Medicinal; D011134:Polysaccharides / Q000378:metabolism
D002352:Carrier Proteins; D017931:DNA Primers; D037102:Lectins; D008565:Membrane Proteins; D037121:Plant Lectins; D011134:Polysaccharides; D002118:Calcium