IDENTIFICATION OF AN ATYPICAL LIPOPROTEIN-BINDING PROTEIN FROM HUMAN AORTIC SMOOTH-MUSCLE AS T-CADHERIN

We have previously described an atypical lipoprotein-binding protein o f about 105 kDa (p105) in membranes of vascular smooth muscle cells (V SMCs) that is distinct from currently known lipoprotein receptors. In the present work we have developed a procedure for purification of p10 5 from human aortic media. Partial sequencing of purified protein has revealed identity of p105 with human T-cadherin. Anti-peptide antisera raised against human T-cadherin recognized a protein spot correspondi ng to the purified p105 on two-dimensional Western blots. The antisera also inhibited LDL binding to p105 on ligand blots. We conclude that the 105 kDa lipoprotein-binding protein present in human VSMCs is T-ca dherin, an unusual glycosylphosphatidylinositol-anchored member of the cadherin family of cell-cell adhesion proteins. (C) 1998 Federation o f European Biochemical Societies.