RESUMEN
The interaction of surface proteins from A431 cells and cellular extracts with nucleic acids was investigated using affinity modification with 32P-labeled reactive oligonucleotide derivatives. Proteins with molecular weights of 68, 46, 38, and 28 kD as well as several low molecular weight proteins capable of binding to nucleic acids were found on the surface of intact cells. It was demonstrated that a protein with molecular weight of 68 kD is exposed at the cell surface, since the treatment of cells with trypsin results in the cleavage of this protein. Disruption of the integrity of the cell membrane (scrapping, treatment with trypsin, or permeabilization of the cell membrane with streptolysin O or saponin) disrupts the interaction of the reactive oligonucleotides with the cell surface proteins. Affinity modification of the cytosolic and membrane-cytosolic cell fractions with labeled oligonucleotides results in the modification of a large number of proteins, where proteins with molecular weights of 68, 46, 38, and 28 kD can be found as minor components. Surface oligonucleotide-binding proteins with molecular weight of ~68 kD were isolated by affinity chromatography after the modification of intact A431 cells with a reactive oligonucleotide derivative. The isolated surface oligonucleotide-binding proteins from A431 cells were sequenced, and one of the proteins was identified as keratin K1.
Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Queratinas/metabolismo , Proteínas de la Membrana/metabolismo , Oligonucleótidos/metabolismo , Animales , Secuencia de Bases , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Membrana Celular/metabolismo , Cromatografía de Afinidad , Electroforesis en Gel de Poliacrilamida , Fluoresceína-5-Isotiocianato , Humanos , Queratinas/química , Ácidos Nucleicos/metabolismo , Unión Proteica , ConejosRESUMEN
Affinity modified with Flu-DAP-p(N)16degU oligonucleotide-binding proteins were isolated by affinity chromatography using Ultrogel A2-anti fluorescein antibodies. After separation by SDS-PAGE the proteins with molecular masses about 68 kDa were MS/MS sequenced and identified as keratin K1, keratin K10, keratin K2e and albumin.