The Cell Adhesion Receptor Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 Regulates Nucleocytoplasmic Trafficking of DNA Polymerase δ-Interacting Protein 38

Esther Klaile,Mario M Müller,Christoph Kannicht,Wolfgang Otto,Bernhard B Singer,Werner Reutter,Björn Öbrink,Lothar Lucka

doi:10.1074/jbc.m701807200

Abstract

The homophilic cell-cell adhesion receptor CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1, CD66a) acts as a regulator of contact-dependent cell survival, differentiation, and growth. It is involved in the control of proliferation in hematopoietic and epithelial cells and can act as a tumor suppressor. In this study, we identify DNA polymerase delta-interacting protein 38 (PDIP38) as a novel binding partner for CEACAM1-L and CEACAM1-S. We show that PDIP38 can occur in the nucleus, in the cytoplasm and at the plasma membrane in NBT-II, IEC18, RBE, and HeLa cells and that the distribution in NBT-II cells is influenced by the confluency of the cells. We also demonstrate that the interaction of CEACAM1 and PDIP38 is of functional importance in NBT-II cells, which co-express the long and the short CEACAM1 isoform. In subconfluent, proliferating NBT-II cells, perturbation of CEACAM1 by antibody clustering induces increased binding to PDIP38 and results in rapid recruitment of PDIP38 to the plasma membrane. The same treatment of confluent, quiescent NBT-II cells leads to a different response, i.e. translocation of PDIP38 to the nucleus. Together, our data show that PDIP38 can shuttle between the cytoplasmic and the nuclear compartments and that its subcellular localization is regulated by CEACAM1, implicating that PDIP38 may constitute a novel downstream target of CEACAM1 signaling.

Highlights

The fate of a cell is controlled by its environment, including the extracellular matrix, neighboring cells, and soluble factors
Characterization of the CEACAM1/PDIP38-binding Properties—To further specify the mutual binding sites, we constructed truncated versions of the CEACAM1-L cytoplasmic domain and the PDIP38 C terminus found in the yeast two-hybrid screen
We identified the PCNA- and DNA polymerase ␦-interacting protein PDIP38 as an interaction partner for both the long and the short CEACAM1 isoforms

Summary

Introduction

The fate of a cell is controlled by its environment, including the extracellular matrix, neighboring cells, and soluble factors. To investigate if any of these phosphorylation events might be involved in nuclear translocation or plasma membrane recruitment of PDIP38, we tested a variety of protein kinase inhibitors for their ability to influence the translocation of PDIP38 upon CEACAM clustering by antibodies Be9.2/GaM.

Results

Conclusion