Identification of 130 kDa cell surface LDL-binding protein from smooth muscle cells as a partially processed T-cadherin precursor.
Atypical cell surface lipoprotein-binding proteins of 105 kDa and 130 kDa are present in membranes of vascular smooth muscle cells. We recently identified the 105 kDa protein from human aortic media as T-cadherin, an unusual glycosylphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion proteins. The goal of the present study was to determine the identity of 130 kDa lipoprotein-binding protein of smooth muscle cells. We applied different approaches that included protein sequencing of purified protein from human aortic media, the use of human T-cadherin peptide-specific antisera, and enzymatic treatment of cultured cells with trypsin and GPI-specific phospholipase C. Our results indicate that the 130 kDa protein is a partially processed form of T-cadherin which is attached to the membrane surface of smooth muscle cells via a GPI anchor and contains uncleaved N-terminal propeptide sequence. Our data disclose that, in contrast to classical cadherins, T-cadherin is expressed on the cell surface in both its precursor (130 kDa) and mature (105 kDa) forms.
Stambolsky
D V
DV
Laboratory of Molecular Endocrinology, Institute of Experimental Cardiology, Cardiology Research Center, 121552, Moscow, Russia.
Kuzmenko
Y S
YS
Philippova
M P
MP
Bochkov
V N
VN
Bespalova
Z D
ZD
Azmuko
A A
AA
Kashirina
N M
NM
Vlasik
T N
TN
Tkachuk
V A
VA
Resink
T J
TJ
D001011:Aorta; D015820:Cadherins / Q000032:analysis* / Q000276:immunology; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D015151:Immunoblotting; D008970:Molecular Weight; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D011498:Protein Precursors / Q000032:analysis*; D011973:Receptors, LDL / Q000032:analysis* / Q000737:chemistry
D015820:Cadherins; D000939:Epitopes; C099972:H-cadherin; D007106:Immune Sera; D011498:Protein Precursors; D011973:Receptors, LDL