Human vascular endothelial cells express a membrane protein complex immunochemically indistinguishable from the platelet VLA-2 (glycoprotein Ia-IIa) complex

Abstract

Endothelial cells express surface molecules that are involved in cell- matrix interaction, including the vitronectin receptor and the fibronectin receptor, both members of a family of cell adhesion receptors (integrins). Here we provide evidence that endothelial cells express a membrane molecule, indistinguishable from the platelet VLA-2 complex, which is a collagen receptor and a member of the integrin family. To identify this endothelial molecule, we have used a monoclonal antibody, CLB-10G11, which recognizes the VLA-2 complex from platelets. The molecule recognized by CLB-10G11 from endothelial cells was characterized as follows. (1) The monoclonal antibody precipitated two proteins from surface-labeled endothelial cells that corresponded to the platelet VLA-2 subunits (glycoprotein Ia and IIa) as judged by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional nonreduced/reduced SDS- PAGE. (2) Preclearing of endothelial cells with monoclonal antibody A- 1A5, an antibody that is directed against the common VLA beta subunit, removed all the CLB-10G11-binding material. (3) Crossed immunoelectrophoresis revealed that CLB-10G11 recognizes a single precipitation arc from either platelets or endothelial cells. Analysis of these two cell types in one gel again revealed one precipitation arc. The antigen of either cell type, recognized by CLB-10G11 could be precipitated by either polyclonal antiplatelet or polyclonal antiendothelial cell antiserum. Hence, it appears that endothelial cells express at least three different surface molecules (the vitronectin receptor, the fibronectin receptor and a collagen receptor), which may play an important role in controlling the anchorage of endothelial cells to the extracellular matrix.

Expression of β1‐integrins, H‐CAM (CD44) and LECAM‐1 in primary gastro‐intestinal B‐cell lymphomas as compared to the adhesion receptor profile of the gut‐associated lymphoid system, tonsil and peripheral lymph node

“…H-CAM, also referred to as Hermes class of homing receptor molecules, Pgp-1, and CD44 antigen , is an 0and N-glycosylated 85to 95-kDa type-I integral membrane protein with a homology region of the cartilage link and proteoglycan core protein (Goldstein et al, 1989) unrelated to LECAM-1 (Stamencovic et al, 1989). It has at least 2 distinct functional domains, namely, a receptor for hyaluronate and a receptor for high endothelial venules (Culty et al, 1990).…”

VLA‐2 is a collagen receptor on endothelial cells

“…a potential proteolytic cleavage site has not been identified within the primary structure of VLA-2 (22). HUVE express VLA-2 as well as other members ofthe VLA family (12). VLA-2 has been shown to be a collagen and laminin receptor on a number of cell types, e.g.…”

“…Endotheiial cells express VLA-2 as well as other members of the VLA family (12,13) and VLA-2 has recently been identified as a receptor for both laminin and collagen on these cells (14). This repott describes the mouse monoclonal antibody RMACl 1 which reacts with a functional epitope on VLA-2 and inhibits HUVE binding to both laminin and collagen.…”

Neuronal differentiation in SH-SY5Y human neuroblastoma cells induces synthesis and secretion of tenascin and upregulation of ?v integrin receptors

“…Then, the specimens were exposed to MAb 13AA8 against neurofilaments or MAb 100EB2 against Tn. For the analysis of Int subunits the following MAbs were used: 102DF5 against Int b 1 , 90BB10 against Int b 3 (Ylänne et al, 1988), 1A9 against Int b 5 (Pasqualini et al, 1993), E 7 P 6 G 10 P 0 against Int b 6 (Weinacker et al, 1994), TS 2/7 against Int a 1 (Hemler et al, 1984), 10G11 against Int a 2 (Giltay et al, 1989), J143 against Int a 3 (Fradet et al, 1984), B5-G10 against Int a 4 (Hemler et al, 1987), BIE5 against Int a 5 (Werb et al, 1989), and GoH3 against Int a 6 ( Sonnenberg et al, 1987). After exposure to the fluorescein isothiocyanate-coupled goat anti-mouse IgG or anti-rat antisera (Jackson Laboratories, West Grove, PA), the specimens were mounted and examined in a Leica Aristoplan microscope equipped with appropriate filters.…”