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Cloning of murine low molecular weight phosphotyrosine protein phosphatase cDNA: identification of a new isoform
Author(s) -
Magherini F,
Giani E,
Raugei G,
Cirri P,
Paoli P,
Modesti A,
Camici G,
Ramponi G
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01241-1
Subject(s) - gene isoform , complementary dna , alternative splicing , microbiology and biotechnology , biology , molecular cloning , biochemistry , isozyme , gene , phosphatase , rna splicing , protein tyrosine phosphatase , immunoprecipitation , gene expression , messenger rna , phosphorylation , enzyme , rna
The low molecular weight phosphotyrosine protein phosphatase (LMW‐PTP) is a 18 kDa cytosolic enzyme, involved in the negative regulation of cell proliferation. In different mammalian species LMW‐PTPs are expressed in two molecular forms produced from a single primary transcript through an alternative splicing mechanism. In this paper we report the cloning, expression and characterization of mouse isoforms of LMW‐PTPs (called m‐IF1 and m‐IF2), very similar to the corresponding rat and human isoenzymes. Moreover we have identified a third cDNA encoding a protein (m‐IF2P) that presents three substitutions compared to m‐IF2. This new isoform is still active on pNPP, although to a lower extent: this reduction is mainly due to the leucine to proline substitution in position 13, within the catalytic loop. The mRNA expression level of this isoform is comparable to those of m‐IF1 and m‐IF2. It is likely that a gene duplication process followed by mutations has generated this new gene.