title: The light chain of CD98 is identified as E16/TA1 protein.
abstract: The 80/40-kDa CD98 protein complex was purified using an anti-CD98 heavy chain monoclonal antibody coupled to Sepharose beads. Eluted proteins were subjected to preparative SDS-polyacrylamide gel electrophoresis, and protein corresponding to the 40-kDa CD98 light chain was excised. Following proteolysis with trypsin, a peptide fragment was sequenced by mass spectrometry. The nine residues obtained were identical to established C-terminal sequences of the human E16 and rat TA1 proteins, suggesting that TA1/E16 protein is the CD98 light chain. Consistent with this, anti-TA1/E16 antibodies specifically immunoblotted the approximately 35-40-kDa light chain present upon immunoprecipitation of the human CD98 complex. Furthermore, anti-CD98 heavy chain antibody specifically co-immunoprecipitated hemagglutinin-tagged light chain from cells transfected with hemagglutinin-tagged E16 cDNA. In conclusion, the CD98 light chain is identical to the TA1/E16 protein, based on partial amino acid sequence identity, antibody cross-reactivity, genetic reconstitution evidence, similar molecular size, and comparable cell distribution.
authors.affiliation: Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Mannion
authors.forename: T V
authors.initials: TV
authors.lastname: Kolesnikova
authors.forename: S H
authors.initials: SH
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: N L
authors.initials: NL
authors.lastname: Thompson
authors.forename: M E
authors.initials: ME
authors.lastname: Hemler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D002460:Cell Line; D027261:Fusion Regulatory Protein-1; D006801:Humans; D027283:Large Neutral Amino Acid-Transporter 1; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D051381:Rats
chemical_list: D015703:Antigens, CD; D002352:Carrier Proteins; D027261:Fusion Regulatory Protein-1; D027283:Large Neutral Amino Acid-Transporter 1; D008565:Membrane Proteins; C000632119:Slc7a5 protein, rat