TY - JOUR
T1 - Isolation of a novel β4 integrin-binding protein (p27(BBP)) highly expressed in epithelial cells
AU - Biffo, Stefano
AU - Sanvito, Francesca
AU - Costa, Silvana
AU - Preve, Laura
AU - Pignatelli, Raffaella
AU - Spinardi, Laura
AU - Marchisio, Pier Carlo
PY - 1997/11/28
Y1 - 1997/11/28
N2 - The integrin β4 has a long cytodomain necessary for hemidesmosome formation. A yeast two-hybrid screen using β4 cytodomain uncovered a protein called p27(BBP) that represents a β4 interactor. Both in yeast and in vitro, p27(BBP) binds the two NH2-terminal fibronectin type III modules of β4, a region required for signaling and hemidesmosome formation. Sequence analysis of p27(BBP) revealed that p27(BBP) was not previously known and has no homology with any isolated mammalian protein, but 85% identical to a yeast gene product of unknown function. Expression studies by Northern analysis and in situ hybridization showed that, in vivo, p27(BBP) mRNA is highly expressed in epithelia and proliferating embryonic epithelial cells. An antibody raised against p27(BBP) COOH-terminal domain showed that all β4-containing epithelial cell lines expressed p27(BBP). The p27(BBP) protein is insoluble and present in the intermediate filament pool. Furthermore, subcellular fractionation indicated the presence of 927(BBP) both in the cytoplasm and in the nucleus. Confocal analysis of cultured cells showed that part of p27(BBP) immunoreactivity was both nuclear and in the membrane closely apposed to β4. These results suggest that the p27(BBP) is an in vivo interactor of β4, possibly linking β4 to the intermediate filament cytoskeleton.
AB - The integrin β4 has a long cytodomain necessary for hemidesmosome formation. A yeast two-hybrid screen using β4 cytodomain uncovered a protein called p27(BBP) that represents a β4 interactor. Both in yeast and in vitro, p27(BBP) binds the two NH2-terminal fibronectin type III modules of β4, a region required for signaling and hemidesmosome formation. Sequence analysis of p27(BBP) revealed that p27(BBP) was not previously known and has no homology with any isolated mammalian protein, but 85% identical to a yeast gene product of unknown function. Expression studies by Northern analysis and in situ hybridization showed that, in vivo, p27(BBP) mRNA is highly expressed in epithelia and proliferating embryonic epithelial cells. An antibody raised against p27(BBP) COOH-terminal domain showed that all β4-containing epithelial cell lines expressed p27(BBP). The p27(BBP) protein is insoluble and present in the intermediate filament pool. Furthermore, subcellular fractionation indicated the presence of 927(BBP) both in the cytoplasm and in the nucleus. Confocal analysis of cultured cells showed that part of p27(BBP) immunoreactivity was both nuclear and in the membrane closely apposed to β4. These results suggest that the p27(BBP) is an in vivo interactor of β4, possibly linking β4 to the intermediate filament cytoskeleton.
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U2 - 10.1074/jbc.272.48.30314
DO - 10.1074/jbc.272.48.30314
M3 - Article
C2 - 9374518
AN - SCOPUS:0030613855
VL - 272
SP - 30314
EP - 30321
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 48
ER -