Th ubiquitously expressed pI(Cln) protein forms homomeric complexes in vitro

Endothelial cells contain a cell-volume sensitive chloride conductance with biophysical properties similar to those of a ubiquitously expressed chloride current that is activated by cell swelling. The latter current has been associated with the I-Cln protein (pI(Cln)) which may be the chloride channel itself or, alternatively, a channel regulator. we were therefore interested in whether pI(Cln) is involved in the endothelial volume-sensitive chloride current. As a first step, we have cloned human pI(Cln) and studied its expression at the protein level. Using a polyclonal antiserum raised against human pI(Cln) we found a widespread expression of pI(Cln), both in endothelial cells and in other cell lines. A characteristic feature of pI(Cln) is its anomalous migration during denaturing polyacrylamide gel electrophoresis. We also demonstrate that bacterially expressed pI(Cln) forms homomeric complexes in vitro. (C) 1996 Academic Press, Inc.