Identification of an additional member of the protein-tyrosine-phosphatase family: evidence for alternative splicing in the tyrosine phosphatase domain.
Protein-tyrosine-phosphatases (protein-tyrosine-phosphate phosphohydrolase, EC 3.13.48) have been implicated in the regulation of cell growth; however, to date few tyrosine phosphatases have been characterized. To identify additional family members, the cDNA for the human tyrosine phosphatase leukocyte common antigen (LCA; CD45) was used to screen, under low stringency, a mouse pre-B-cell cDNA library. Two cDNA clones were isolated and sequence analysis predicts a protein sequence of 793 amino acids. We have named the molecule LRP (LCA-related phosphatase). RNA transfer analysis indicates that the cDNAs were derived from a 3.2-kilobase mRNA. The LRP mRNA is transcribed in a wide variety of tissues. The predicted protein structure can be divided into the following structural features: a short 19-amino acid leader sequence, an exterior domain of 123 amino acids that is predicted to be highly glycosylated, a 24-amino acid membrane-spanning region, and a 627-amino acid cytoplasmic region. The cytoplasmic region contains two approximately 260-amino acid domains, each with homology to the tyrosine phosphatase family. One of the cDNA clones differed in that it had a 108-base-pair insertion that, while preserving the reading frame, would disrupt the first protein-tyrosine-phosphatase domain. Analysis of genomic DNA indicates that the insertion is due to an alternatively spliced exon. LRP appears to be evolutionarily conserved as a putative homologue has been identified in the invertebrate Styela plicata.
Matthews
R J
RJ
Department of Pathology, Washington University School of Medicine, Saint Louis, MO 63110.
Cahir
E D
ED
Thomas
M L
ML
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D000943:Antigens, Differentiation / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D015342:DNA Probes; D015723:Gene Library; D006023:Glycoproteins / Q000235:genetics*; D006649:Histocompatibility Antigens / Q000235:genetics; D006801:Humans; D017493:Leukocyte Common Antigens; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D010749:Phosphoprotein Phosphatases / Q000235:genetics*; D017027:Protein Tyrosine Phosphatases; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D011956:Receptors, Cell Surface; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D015703:Antigens, CD; D000943:Antigens, Differentiation; D015342:DNA Probes; D006023:Glycoproteins; D006649:Histocompatibility Antigens; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D010749:Phosphoprotein Phosphatases; D017493:Leukocyte Common Antigens; C516841:PTPRA protein, human; D017027:Protein Tyrosine Phosphatases; C516843:Ptpra protein, mouse; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4