Cloning and expression of a cytosolic megakaryocyte protein-tyrosine-phosphatase with sequence homology to retinaldehyde-binding protein and yeast SEC14p

Protein tyrosine phosphorylation is important in the regulation of cell growth, the cell cycle, and malignant transformation. We have cloned a cDNA that encodes a cytosolic protein-tyrosine-phosphatase (PTPase), MEG2, from MEG-01 cell and human umbilical vein endothelial cell cDNA libraries. The 4-k...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1992-04, Vol.89 (7), p.2980-2984
Main Authors: GU, M, WARSHAWSKY, I, MAJERUS, P. W
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Analytical, structural and metabolic biochemistry
Bacteria
Base Sequence
Biochemistry
Biological and medical sciences
Carrier Proteins - genetics
Cloning, Molecular
Cytosol - enzymology
Deoxyribonucleic acid
DNA
Endothelium, Vascular - enzymology
Enzymes and enzyme inhibitors
Fundamental and applied biological sciences. Psychology
Gene Expression
genes
Genes, Fungal
Humans
Hydrolases
Medical research
Megakaryocytes - enzymology
Membrane Proteins
Molecular Sequence Data
Multidisciplinary Sciences
Phospholipid Transfer Proteins
Protein Tyrosine Phosphatases - genetics
Proteins
Recombinant Proteins - metabolism
retinaldehyde-binding protein
RNA, Messenger - genetics
Saccharomyces cerevisiae - genetics
Saccharomyces cerevisiae Proteins
Science & Technology
Science & Technology - Other Topics
SEC14p protein
Sequence Alignment
umbilical cord
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Summary:Protein tyrosine phosphorylation is important in the regulation of cell growth, the cell cycle, and malignant transformation. We have cloned a cDNA that encodes a cytosolic protein-tyrosine-phosphatase (PTPase), MEG2, from MEG-01 cell and human umbilical vein endothelial cell cDNA libraries. The 4-kilobase cDNA sequence of PTPase MEG2 corresponds in length to the mRNA transcript detected by Northern blotting. The predicted open reading frame encodes a 68-kDa protein composed of 593 amino acids and has no apparent signal or transmembrane sequences, suggesting that it is a cytosolic protein. The C-terminal region has a PTPase catalytic domain that has 30-40% amino acid identity to other known PTPases. The N-terminal region has 254 amino acids that are 28% identical to cellular retinaldehyde-binding protein and 24% identical to yeast SEC14p, a protein that has phosphatidylinositol transfer activity and is required for protein secretion through the Golgi complex in yeast. Recombinant PTPase MEG2 expressed in Escherichia coli possesses PTPase activity. PTPase MEG2 mRNA was detected in 12 cell lines tested, which suggests that this phosphatase is widely expressed. The structure of PTPase MEG2 implies that a tyrosine phosphatase could participate in the transfer of hydrophobic ligands or in functions of the Golgi apparatus.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.89.7.2980