Calcium‐dependent binding of uteroglobin (PCB‐BP/CCSP) to negatively charged phospholipid liposomes

Abstract

To investigate interactions between the polyehlorinated biphenyl-binding protein uteroglobin and phospholipids, we used a liposome-pelletting assay. PCB-BPluteroglobin bound to liposomes made from negatively charged phospholipids (PtdSer and Ptdlns) in the presence of 5 mM calcium. No binding to liposomes made from phospholipids without net charge (PtdChol and PtdEtn) was observed, nor could we detect binding in the absence of calcium or when magnesium was substituted for calcium. This suggests that PCB-BPluteroglobin can bind to phospholipids in vivo and may have a role in the phospbolipid homeostasis of the airway and/or secretory pathway of the Clara cell.