Identification, Cloning, and Expression of a Cytosolic Megakaryocyte Protein-Tyrosine-Phosphatase with Sequence Homology to Cytoskeletal Protein 4.1

We have isolated a cDNA encoding a third type of protein-tyrosine-phosphatase. We screened human megakaryoblastic cell line (MEG-01) and umbilical vein endothelial cell cDNA libraries to obtain a 3.7-kilobase cDNA designated PTPase MEG. Northern blot analysis of MEG-01 RNA detected a 3.7-kilobase tr...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1991-07, Vol.88 (13), p.5867-5871
Main Authors: Gu, Minxiang, York, John D., Warshawsky, Ilka, Majerus, Philip W.
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Amino acids
Analytical, structural and metabolic biochemistry
band 4.1 protein
Base Sequence
Biological and medical sciences
Blotting, Northern
CDNA libraries
Cell lines
Cloning, Molecular
Complementary DNA
Cytoskeletal Proteins - chemistry
Cytosol - enzymology
DNA - genetics
Enzymes and enzyme inhibitors
Escherichia coli
Fundamental and applied biological sciences. Psychology
Gene Expression
genes
Human umbilical vein endothelial cells
Humans
Hydrolases
megakaryocytes
Megakaryocytes - enzymology
Membrane Proteins - chemistry
Molecular Sequence Data
Neuropeptides
Oligonucleotides - chemistry
Phosphatases
Phosphoprotein Phosphatases - genetics
Phosphoprotein Phosphatases - metabolism
Phosphorylation
Polymerase Chain Reaction
Protein Tyrosine Phosphatase, Non-Receptor Type 4
Protein Tyrosine Phosphatases - genetics
Protein Tyrosine Phosphatases - metabolism
Recombinant Proteins - metabolism
Restriction Mapping
RNA
RNA, Messenger - genetics
T lymphocytes
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Description
Summary:We have isolated a cDNA encoding a third type of protein-tyrosine-phosphatase. We screened human megakaryoblastic cell line (MEG-01) and umbilical vein endothelial cell cDNA libraries to obtain a 3.7-kilobase cDNA designated PTPase MEG. Northern blot analysis of MEG-01 RNA detected a 3.7-kilobase transcript, suggesting that a full-length cDNA has been identified. PTPase MEG cDNA contains an open reading frame of 926 amino acids. The cDNA has a G+C-rich 5' untranslated region of 771 nucleotides that has the potential to form stable stem-loop structures and has two upstream ATG codons. The predicted protein (Mr= 105,910) has no apparent membrane-spanning region and contains a single protein-tyrosine-phosphatase domain (amino acids 659-909) that is 35-40% identical to previously described tyrosine-phosphatase domains. The recombinant phosphatase domain possesses protein-tyrosine-phosphatase activity when expressed in Escherichia coli. The amino-terminal region (amino acids 31-367) is 45% identical to the amino terminus of human erythrocyte protein 4.1, a cytoskeletal protein. The identification of a protein-tyrosine-phosphatase that is related to cytoskeletal proteins implies that cell signaling activities reside not only in transmembrane receptors but in cytoskeletal elements as well.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.88.13.5867