Annexin II Modulates Volume-activated Chloride Currents in Vascular Endothelial Cells

doi:10.1074/jbc.271.48.30631

Annexin II Modulates Volume-activated Chloride Currents in Vascular Endothelial Cells*

From the Laboratorium voor Fysiologie, KU Leuven, B-3000 Leuven, Belgium
^§ Clinical Research Group Endothelial Cell Biology, University of Münster, D-48149 Münster
** Department of Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Federal Republic of Germany

^‡ To whom correspondence should be addressed:
Laboratorium voor Fysiologie, Campus Gasthuisberg, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium.
Tel.: 0032-16-34 5726; Fax: 0032-16-34 5991; E-mail: bernd.nilius{at}med.kuleuven.ac.be.

Abstract

The membrane-associated, microfilament-binding protein annexin II is abundantly expressed in endothelial cells from calf pulmonary artery (CPAE cells). We have analyzed its role in the regulation of volume-activated chloride currents (I_{Cl, vol}) by loading the cells via the patch pipette with a peptide comprising the N-terminal 14 residues of annexin II. This sequence harbors the binding site for the intracellular annexin II ligand, p11, and the peptide interferes with the annexin II-p11 complex formation. Loading of a CPAE cell with this peptide caused a gradual decrease in the amplitude of I_{Cl, vol} during repetitive stimulations with a 28% hypotonic extracellular solution. This run down of the current was virtually absent in untreated cells and in cells that were loaded with a mutated 14-amino acid peptide, which has a single amino acid replacement known to result in a more than 1000 times reduced affinity for binding to p11. We conclude that annexin II-p11 complex formation is either directly or indirectly involved in the activation of I_{Cl, vol} in endothelial cells.

Footnotes

↵^¶ Supported by a grant from Dienst Wetenschappelijke, Technische, en Culturele Aangelegenheiden, Belgium, and the Onderzoeksraad KU Leuven. Present address: University Medical School, Dept. of Physiology, University of Debrecen, H-4012 Debrecen, Hungary.
↵^∥ Supported by a grant from the Onderzoeksraad KU Leuven.
↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

CPAE

calf pulmonary artery endothelial cells

HTS

hypotonic solution

MDCK

Madin-Darby canine kidney cells.
↵² T. Voets, G. Droogmans, V. Manalopoulos, and B. Nilius, unpublished observations.
- Received May 21, 1996.
- Revision received September 16, 1996.