Alpha 2 beta 1 integrins from different cell types show different binding specificities.
Purified alpha 2 beta 1 integrin from human platelets was compared in its function and immunoreactivity to alpha 2 beta 1 from endothelial cells. Both alpha 2 beta 1 integrins bound to type I collagen-Sepharose and had indistinguishable immunoreactivities when analyzed by a panel of monoclonal and polyclonal alpha 2-specific antibodies. However, functional analysis using rechromatography of purified receptors on laminin and collagen-Sepharose showed that endothelial alpha 2 beta 1 was able to bind to laminin, whereas its counterpart from platelets did not. Moreover, a receptor binding assay indicated that, in contrast to platelets, endothelial cells might also use alpha 2 beta 1 to bind to fibronectin. These results suggest that the alpha 2 beta 1 binding specificity may be modulated by cell-type specific factors.
Kirchhofer
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La Jolla Cancer Research Foundation, California 92037.
Languino
L R
LR
Ruoslahti
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E
Pierschbacher
M D
MD
D001665:Binding Sites; D001792:Blood Platelets / Q000378:metabolism; D002846:Chromatography, Affinity; D003094:Collagen / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004727:Endothelium / Q000166:cytology / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D011233:Precipitin Tests; D011956:Receptors, Cell Surface / Q000378:metabolism; D038981:Receptors, Collagen; D014470:Umbilical Cord / Q000166:cytology / Q000378:metabolism
D016023:Integrins; D011956:Receptors, Cell Surface; D038981:Receptors, Collagen; D003094:Collagen