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Characterization of a variant of PAC-1 in large granular lymphocyte leukemia
- Source :
-
Protein Expression & Purification . Nov2003, Vol. 32 Issue 1, p52. 9p. - Publication Year :
- 2003
-
Abstract
- Phosphatase in activated T cells (PAC-1) is a mitogen-induced early responsive gene. It encodes a 32 kDa tyrosine–threonine dual specificity phosphatase. Constitutive expression of PAC-1 leads to an inhibition of MAP kinase activity in vivo. Such constitutive expression was reported in HTLV-1 infected cell lines. In the present study, we observed the constitutive over-expression of two transcripts related to PAC-1 in large granular lymphocyte (LGL) leukemia. By screening a LGL leukemia cDNA library using the <f>3′</f> end of a PAC-1 probe, we obtained a clone (clone 8) which retains one and one half introns, excludes two exons, and matches one hundred percent with a DNA sequence on chromosome 2. The deduced amino acid sequence of the predicted protein contains 170 amino acids and is 144 amino acids shorter than PAC-1. When we expressed this protein in Escherichia coli as a GST-fusion protein, a 45 kDa (19 kDa PAC-1 variant + 26 kDa GST protein) protein was obtained. The expressed protein was purified to near homogeneity by using a glutathione affinity column. The purified protein did not have any intrinsic phosphatase activity when assayed in vitro. But when this purified protein was added to a phosphatase assay system in combination with a recombinant dual specificity phosphatase, CL100, enhanced phosphatase activity was observed. The significance of the constitutive over-expression and its physiological role of this protein remain to be established in leukemic LGL. [Copyright &y& Elsevier]
- Subjects :
- *PHOSPHATASES
*T cells
*MITOGENS
*CLONING
Subjects
Details
- Language :
- English
- ISSN :
- 10465928
- Volume :
- 32
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Protein Expression & Purification
- Publication Type :
- Academic Journal
- Accession number :
- 11172512
- Full Text :
- https://doi.org/10.1016/S1046-5928(03)00237-7