Analysis of the interactions between BP180, BP230, plectin and the integrin alpha6beta4 important for hemidesmosome assembly.
Hemidesmosomes (HDs) are multi-protein complexes that promote stable adhesion of epithelial cells to the underlying extracellular matrix. We assessed the interactions between different hemidesmosomal components with each other, mapped the binding sites and studied the importance of these interactions for HD assembly in yeast two-hybrid and cell-transfection assays. The results show that: (1) bullous pemphigoid antigen (BP) 180 binds not only to BP230, but also to plectin. The interactions between these proteins are facilitated by the Y subdomain in the N-terminal plakin domain of BP230 and plectin, and residues 145-230 of the cytoplasmic domain of BP180; (2) different, but overlapping, sequences on BP180 mediate binding to beta4, which, in turn associates with BP180 via its third fibronectin type III repeat; (3) sequences in the N-terminal extremity of BP230 mediate its binding to beta4, which requires the C-terminal end of the connecting segment up to the fourth FNIII repeat of the beta4 subunit. (4) Finally, cell-transfection studies showed that the localization of BP230 into hemidesmosome-like structures depends on its Z-Y subdomains as well as on the availability of BP180. By having further uncovered interactions between various hemidesmosomal components, mapped the involved binding sites and dissected a hierarchy of interactions relevant for their topogenic fate, our findings give novel insights into the molecular organization of hemidesmosomes.
Koster
Jan
J
The Netherlands Cancer Institute, Division of Cell Biology, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Geerts
Dirk
D
Favre
Bertrand
B
Borradori
Luca
L
Sonnenberg
Arnoud
A
D001324:Autoantigens / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins; D002448:Cell Adhesion / Q000502:physiology*; D002461:Cell Line, Transformed; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D022002:Hemidesmosomes / Q000378:metabolism*; D006801:Humans; D039161:Integrin alpha6beta4 / Q000235:genetics / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D010391:Pemphigoid, Bullous / Q000235:genetics / Q000378:metabolism; D051190:Plectin; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D014162:Transfection; D020798:Two-Hybrid System Techniques; D000097805:Collagen Type XVII
D001324:Autoantigens; D002352:Carrier Proteins; D003094:Collagen; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D039161:Integrin alpha6beta4; D007381:Intermediate Filament Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D051190:Plectin; D000097805:Collagen Type XVII; C486268:DST protein, human; C495332:PLEC protein, human