Abstract
The human cell proliferation-associated nucleolar protein p120 was found in a variety of human cancer specimens but not in most normal resting cells. Polyclonal antibodies raised against bacterially expressed p120 were used to immunoprecipitate the p120 protein isolated from 32P-labeled HeLa cells. The p120 protein was phosphorylated at serine, threonine and tyrosine residues. A tryptic peptide map showed it contained three labeled peptides. One of these peptides comigrated with a p120 peptide phosphorylated in vitro by casein kinase II. This peptide was phosphorylated in vitro both at Ser-181 and Thr-185. This region is juxtaposed to the epitope site recognized by the anti-p120 monoclonal antibody.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Amino Acids / analysis
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Carrier Proteins / genetics
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Carrier Proteins / isolation & purification
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Cloning, Molecular
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HeLa Cells / metabolism
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Humans
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Maltose-Binding Proteins
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Molecular Sequence Data
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Nuclear Proteins / genetics
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Nuclear Proteins / immunology
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Nuclear Proteins / isolation & purification
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Nuclear Proteins / metabolism*
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Peptide Fragments / isolation & purification
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Phosphorylation
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Restriction Mapping
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Trypsin
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tRNA Methyltransferases
Substances
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Amino Acids
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Carrier Proteins
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Maltose-Binding Proteins
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Nuclear Proteins
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Peptide Fragments
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NOP2 protein, human
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tRNA Methyltransferases
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Trypsin