RGD Reference Report - Calmodulin binds to specific sequences in the cytoplasmic domain of C-CAM and down-regulates C-CAM self-association. - Rat Genome Database

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Calmodulin binds to specific sequences in the cytoplasmic domain of C-CAM and down-regulates C-CAM self-association.

Authors: Edlund, M  Blikstad, I  Obrink, B 
Citation: Edlund M, etal., J Biol Chem. 1996 Jan 19;271(3):1393-9.
RGD ID: 11059582
Pubmed: (View Article at PubMed) PMID:8576129

C-CAM is a cell adhesion molecule belonging to the immunoglobulin supergene family and is known to mediate calcium-independent homophilic cell-cell binding. Two major isoforms, C-CAM1 and C-CAM2, which differ in their cytoplasmic domains, have been identified. Previous investigations have demonstrated that both cytoplasmic domains can bind calmodulin in a calcium-dependent reaction. In this investigation, peptides corresponding to the cytoplasmic domains of C-CAM were synthesized on cellulose membranes and used to map the binding sites for 125I-labeled calmodulin. Both C-CAM1 and C-CAM2 had one strong calmodulin-binding site in the membrane-proximal region. Those binding regions were conserved in C-CAM from rat, mouse, and man. In addition, C-CAM1 from rat and mouse contained a weaker binding site in the distal region of the cytoplasmic domain. Biosensor experiments were performed to determine rate and equilibrium constants of the C-CAM/calmodulin interaction. An association rate constants of 3.3 x 10(5) M-1 s-1 and two dissociation rate constants of 2.2 x 10(-2) and 3.1 x 10(-5) s-1 were determined. These correspond to equilibrium dissociation constants of 6.7 x 10(-8) and 9.4 x 10(-11) M, respectively. In dot-blot binding experiments, it was found that binding of calmodulin causes a down-regulation of the homophilic self-association of C-CAM. This suggests that calmodulin can regulate the functional activity of C-CAM.

Annotation

Gene Ontology Annotations    

Biological Process

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Ceacam1  (CEA cell adhesion molecule 1)

Objects referenced in this article
Gene Calm1 calmodulin 1 Rattus norvegicus
Gene Calm2 calmodulin 2 Rattus norvegicus
Gene Calm3 calmodulin 3 Rattus norvegicus

Additional Information