p27(BBP/eIF6) is an evolutionarily conserved protein that was originally identified as p27(BBP), an interactor of the cytoplasmic domain of integrin beta4 and, independently, as the putative translation initiation factor eIF6. To establish the in vivo function of p27(BBP/eIF6), its topographical distribution was investigated in mammalian cells and the effects of disrupting the corresponding gene was studied in the budding yeast, Saccharomyces cerevisiae. In epithelial cells containing beta4 integrin, p27(BBP/eIF6) is present in the cytoplasm and enriched at hemidesmosomes with a pattern similar to that of beta4 integrin. Surprisingly, in the absence and in the presence of the beta4 integrin subunit, p27(BBP/eIF6) is in the nucleolus and associated with the nuclear matrix. Deletion of the IIH S. cerevisiae gene, encoding the yeast p27(BBP/eIF6) homologue, is lethal, and depletion of the corresponding gene product is associated with a dramatic decrease of the level of free ribosomal 60S subunit. Furthermore, human p27(BBP/eIF6) can rescue the lethal effect of the iihDelta yeast mutation. The data obtained in vivo suggest an evolutionarily conserved function of p27(BBP/eIF6) in ribosome biogenesis or assembly rather than in translation. A further function related to the beta4 integrin subunit may have evolved specifically in higher eukaryotic cells.
The beta4 integrin interactor p27(BBP/eIF6) is an essential nuclear matrix protein involved in 60S ribosomal subunit assembly / F. Sanvito, S. Piatti, A. Villa, M. Bossi, G. Lucchini, P.C. Marchisio, S. Biffo. - In: THE JOURNAL OF CELL BIOLOGY. - ISSN 0021-9525. - 144:5(1999 Mar 08), pp. 823-837.
|Titolo:||The beta4 integrin interactor p27(BBP/eIF6) is an essential nuclear matrix protein involved in 60S ribosomal subunit assembly|
|Parole Chiave:||epithelial cells; yeast; nucleolus; hemidesmosomes; intermediate filaments; amino acid sequence; antigens, nuclear; base sequence; carrier proteins; cell nucleolus; dna primers; eukaryotic initiation factors; fluorescent antibody technique, indirect; humans; immunohistochemistry; intermediate filament proteins; microscopy, electron; mitosis; molecular sequence data; nuclear proteins; recombinant proteins; ribosomal proteins; saccharomyces cerevisiae; sequence homology, amino acid; phosphoproteins; ribosomes; saccharomyces cerevisiae proteins|
|Settore Scientifico Disciplinare:||Settore BIO/06 - Anatomia Comparata e Citologia|
|Data di pubblicazione:||8-mar-1999|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1083/jcb.144.5.823|
|Appare nelle tipologie:||01 - Articolo su periodico|