title: Downregulation of phospho-tyrosine phosphatases in a macrophage tumor.
abstract: We provide evidence for the downregulation of phospho-tyrosine phosphatases (PTPases) in malignancy. AK-5, a rat macrophage tumor, shows the downregulation of the transcripts of two non-receptor-type PTPases, PTP-1 and PTP-S. Though downregulated fourfold, the genomic organization of PTP-S is unaltered. There is no gross alteration of the PTPase activity in AK-5 as compared to macrophages. Immunoblot analysis reveals no significant change in the total phospho-tyrosine levels in AK-5, but there is a qualitative difference in the pattern between AK-5 and macrophages. Our results lend credence to the conjecture that PTPases also might be involved in malignancy.
authors.affiliation: Centre for Cellular and Molecular Biology, Hyderabad, India.
authors.forename: T S
authors.initials: TS
authors.lastname: Sridhar
authors.forename: G
authors.initials: G
authors.lastname: Swarup
authors.forename: A
authors.initials: A
authors.lastname: Khar
mesh_terms: D000818:Animals; D004273:DNA, Neoplasm / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D015321:Gene Rearrangement; D015151:Immunoblotting; D008264:Macrophages / Q000201:enzymology*; D009693:Nucleic Acid Hybridization; D019000:Phosphotyrosine; D014176:Protein Biosynthesis; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D004273:DNA, Neoplasm; D012333:RNA, Messenger; D019000:Phosphotyrosine; D014443:Tyrosine; D017027:Protein Tyrosine Phosphatases