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Identification and characterization of a novel protein that regulates RNA–protein interaction
Author(s) -
Hod Yaacov,
Pentyala Srinivas N.,
Whyard Terry C.,
ElMaghrabi M. Raafat
Publication year - 1999
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19990301)72:3<435::aid-jcb12>3.0.co;2-h
Subject(s) - identification (biology) , computational biology , characterization (materials science) , protein–protein interaction , microbiology and biotechnology , rna , biology , chemistry , genetics , nanotechnology , gene , ecology , materials science
In a previous study [Nachaliel et al., 1993], we identified an RNA‐binding protein (RBP) in FTO‐2B rat hepatoma cells whose activity was stimulated upon the dissociation of a protein factor. We report in this article that the RBP is a complex protein of about 400 kDa, composed of RNA‐binding subunit(s) (RBS), and regulatory subunit(s) (RS). We purified the RS to near‐homogeneity (M r ∼25,000) and determined the amino acid sequence of a peptide derived from RS. On the basis of this sequence information, the cDNA for RS was obtained. Recombinant RS protein expressed in Escherichia coli had the capacity to bind RBS and inhibit its RNA‐binding activity. The cDNA contains the complete coding sequence because the recombinant protein has the same electrophoretic mobility as that of the native RS in SDS‐polyacrylamide gels. Sequence comparison showed that RS is almost identical to DJ‐1, a recently discovered protein with an oncogenic potential, and CAP1, a rat sperm protein. However, the protein does not contain any known motifs that can provide a clue as to its exact function. Indirect immunofluorescence analyses showed that in addition to the cytoplasm, where RS is associated with microtubular filaments, the polypeptide is localized to the cell nucleus. The possible role of RS is discussed. J. Cell. Biochem. 72:435–444, 1999. © 1999 Wiley‐Liss, Inc.