Mp. Philippova et al., T-CADHERIN AND SIGNAL-TRANSDUCING MOLECULES CO-LOCALIZE IN CAVEOLIN-RICH MEMBRANE DOMAINS OF VASCULAR SMOOTH-MUSCLE CELLS, FEBS letters, 429(2), 1998, pp. 207-210
Cadherins are a family of cellular adhesion proteins mediating homotyp
ic cell-cell binding. In contrast to classical cadherins, T-cadherin d
oes not possess the transmembrane and cytosolic domains known to be es
sential for tight mechanical coupling of cells, and is instead attache
d to the cell membrane by a glycosylphosphatidylinositol (GPI) anchor.
This study explores the hypothesis that T-cadherin might function as
a signal-transducing protein. Membranes from human and rat vascular sm
ooth muscle cells were fractionated using Triton X-100 solubilization
and density gradient centrifugation techniques. We demonstrate that T-
cadherin is enriched in a minor detergent-insoluble low-density membra
ne domain and codistributes with caveolin, a marker of caveolae. This
domain was enriched in other GPI-anchored proteins (CD-59, uPA recepto
r) and signal-transducing molecules (G alpha s protein and Src-family
kinases), but completely excluded cell-cell and cell-matrix adhesion m
olecules (N-cadherin and beta 1-integrin). Coupling of T-cadherin with
signalling molecules within caveolae might enable cellular signal tra
nsduction. (C) 1998 Federation of European Biochemical Societies.