Localization of a Critical Diphtheria Toxin-Binding Domain to the C-Terminus of the Mature Heparin-Binding EGF-like Growth Factor Region of the Diphtheria Toxin Receptor

1995 ◽  
Vol 206 (2) ◽  
pp. 710-717 ◽  
Author(s):  
K.P. Hooper ◽  
L. Eidels
Cell ◽  
1992 ◽  
Vol 69 (6) ◽  
pp. 1051-1061 ◽  
Author(s):  
Joseph G. Naglich ◽  
James E. Metherall ◽  
David W. Russell ◽  
Leon Eidels

1995 ◽  
Vol 129 (6) ◽  
pp. 1691-1705 ◽  
Author(s):  
K Nakamura ◽  
R Iwamoto ◽  
E Mekada

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the EGF family of growth factors, which interact with EGF receptor to exert mitogenic activity. The membrane-anchored form of HB-EGF, proHB-EGF, is biologically active, providing mitogenic stimulation to neighboring cells in a juxtacrine mode. ProHB-EGF forms a complex with diphtheria toxin receptor-associated protein (DRAP27)/CD9, a tetra membrane-spanning protein that upregulates the juxtacrine mitogenic activity of proHB-EGF. We explored whether other proteins associate with DRAP27/CD9 and proHB-EGF. Immunoprecipitation with anti-DRAP27/CD9 resulted in preferential coprecipitation of integrin alpha 3 beta 1 from Vero cell, A431 cell and MG63 cell lysates. Anti-integrin alpha 3 or anti-integrin beta 1 coprecipitated DRAP27/CD9 from the same cell lysates. Chemical cross-linking confirmed the physical association of DRAP27/CD9 and integrin alpha 3 beta 1. Using Vero-H cells, which overexpress HB-EGF, we also demonstrated the association of proHB-EGF with DRAP27/CD9 and integrin alpha 3 beta 1. Moreover, colocalization of proHB-EGF, DRAP27/CD9, and integrin alpha 3 beta 1 at cell-cell contact sites was observed by double-immunofluorescence staining. At cell-cell contact sites, DRAP27/CD9 was highly coincident with alpha-catenin and vinculin, suggesting that DRAP27/CD9, proHB-EGF, and integrin alpha 3 beta 1 are colocalized with adherence junction-locating proteins. These results indicate that direct interaction of growth factors and cell adhesion molecules may control cell proliferation during the cell-cell adhesion process.


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