ANALYSIS OF THE TUMOR-ASSOCIATED ANTIGEN TSP-180 - IDENTITY WITH ALPHA-6-BETA-4 IN THE INTEGRIN SUPERFAMILY

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  • 15 September 1989
    • journal article
    • research article
    • Vol. 264  (26) , 15515-15521
Abstract
The tumor-associated antigen complex, TSP-180, was previously defined in carcinoma cell lines and found to be expressed in higher amounts in tumor than in normal tissue. Here, the mouse TSP-180 complex is shown to consist of three related proteins (bands 1, 2, and 3) associated with a distinct protein (band 5) that is probably derived from a precursor protein (band 4). All of these proteins are cell surface glycoproteins, and the largest protein (band 1) can be readily labeled with 32PO4. The mouse TSP-180 complex described here strongly resembles the recently described human integrin .alpha.6-.beta.4 complex. This homology was confirmed using two distinct rat anti-.alpha.6 monoclonal antibodies, each of which recognized both human .alpha.6-.beta.4 and mouse TSP-180 complexes. Furthermore, the TSP-180 band 5 protein (mouse .alpha.6) had an N-terminal sequence identical to that of human .alpha.6. Finally, two different monoclonal antibodies are described, 346-11A and 439-9B, which directly recognize the multiple forms of mouse and human .beta.4 proteins, respectively.