title: The cell adhesion molecule C-CAM is a substrate for tissue transglutaminase.
abstract: C-CAM, a ubiquitously expressed cell adhesion molecule belonging to the carcinoembryonic antigen family, appears as two co-expressed isoforms, C-CAM-L and C-CAM-S, with different cytoplasmic domains, that can form homodimers in epithelial cells. In addition, C-CAM-L has been found in large molecular weight forms suggesting posttranslational, covalent modification. Here we have investigated the possibility that the cytoplasmic domain of C-CAM-L can act as a transglutaminase substrate. Glutathione S-transferase fusion proteins of the cytoplasmic domains of rat and mouse C-CAM-L as well as free cytoplasmic domains, released by thrombin cleavage from the fusion proteins, were converted into covalent dimers by tissue transglutaminase. These results demonstrate that the cytoplasmic domains of rat and mouse C-CAM-L are substrates for tissue transglutaminase, and lend support to the notion that higher molecular weight forms of C-CAM-L are formed by transglutaminase modification.
authors.affiliation: Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, Stockholm, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Hunter
authors.forename: K
authors.initials: K
authors.lastname: Sigmundsson
authors.forename: N
authors.initials: N
authors.lastname: Beauchemin
authors.forename: B
authors.initials: B
authors.lastname: Obrink
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006023:Glycoproteins; D006168:Guinea Pigs; D008099:Liver / Q000201:enzymology; D051379:Mice; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013379:Substrate Specificity; D011503:Transglutaminases / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C069847:CD66 antigens; C087701:Ceacam2 protein, mouse; D015815:Cell Adhesion Molecules; D006023:Glycoproteins; D011993:Recombinant Fusion Proteins; D011503:Transglutaminases; D005982:Glutathione Transferase; D000251:Adenosine Triphosphatases