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Updated: Aug 9, 2026

Oligopeptide Competition Assay for Phosphorylation Site Determination
Published on: May 18, 2017
Characterization of protein kinase C-mediated phosphorylation of the short cytoplasmic domain isoform of C-CAM
M Edlund1, K Wikström, R Toomik
1Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, Stockholm, Sweden.
Abstract:
C-CAM is a ubiquitously expressed cell adhesion molecule belonging to the carcinoembryonic antigen family. Two co-expressed isoforms, C-CAM-L and C-CAM-S, are known, having different cytoplasmic domains both of which can be phosphorylated in vivo. Here we have characterized the PKC-mediated phosphorylation of the short cytoplasmic domain isoform, C-CAM-S. Phorbol myristyl acetate induced phosphorylation of C-CAM-S in transfected CHO cells. Using synthetic peptides and Edman degradation we identified Ser449 as the PKC-phosphorylated amino acid residue. Binding experiments with modified peptides indicated that this phosphorylation decreases the ability of the cytoplasmic domain of C-CAM-S to bind calmodulin.
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