共 22 条
Identification of an IGF-1R kinase regulatory phosphatase using the fission yeast Schizosaccharomyces pombe and a GFP tagged IGF-1R in mammalian cells
被引:20
作者:
Buckley, DA
[1
]
Loughran, G
[1
]
Murphy, G
[1
]
Fennelly, C
[1
]
O'Connor, R
[1
]
机构:
[1] Natl Univ Ireland Univ Coll Cork, Dept Biochem, Cell Biol Lab, Biosci Res Inst, Cork, Ireland
来源:
JOURNAL OF CLINICAL PATHOLOGY-MOLECULAR PATHOLOGY
|
2002年
/
55卷
/
01期
基金:
英国惠康基金;
关键词:
D O I:
10.1136/mp.55.1.46
中图分类号:
R36 [病理学];
学科分类号:
100104 ;
摘要:
Aims: To study the regulation of type 1 insulin like growth factor receptor (IGF-1 R) tyrosine kinase activity using the fission yeast Schizosaccharomyces pombe and a green fluorescent protein (GFP) tagged, full length IGF-1 R. Methods: The beta chain of the IGF-1 R (betawt) was expressed under inducible conditions in the fission yeast S pombe. Western blot analysis with antiphosphotyrosine antibodies was used to assess the kinase activity of betawt. A GFP tagged IGF-1 R (GFP-IGF-1 R) was constructed to study the tyrosine kinase activity of the full length IGF-1 R. The signalling capabilities of GFP-IGF-1 R in response to IGF-1 stimulation were investigated in transiently transfected fibroblasts. Immunofluorescent staining for cellular phosphotyrosine content was used to assess the localisation and tyrosine kinase activity of GFP-IGF-1 R. Results: The betawt protein displayed functional tyrosine kinase activity in S pombe and phosphorylated endogenous yeast proteins. In response to IGF-1 stimulation, the GFP-IGF-1 R became autophosphorylated and also activated the phosphatidylinositol 3-kinase and mitogen activated protein kinase pathways. Tyrosine phosphorylation and kinase activity of the GFP-IGF-1 R could be visualised by immunofluorescence with antiphosphotyrosine antibodies. Coexpression of a mammalian tyrosine phosphatase PTP 1 B with betawt completely inhibited this tyrosine kinase activity in yeast and also reduced the tyrosine phosphorylation in COS cells transfected with the GFP-IGF-1 R. Conclusions: Schizosaccharomyces pombe can be used to analyse the tyrosine kinase activity of the IGF-1 R beta chain and its regulation by tyrosine phosphatases. In addition, the regulation of IGF-1 R tyrosine kinase activity can be studied using a GFP tagged IGF-1 R. Using both of these methods, IGF-1 R kinase activity was shown to be inhibited by the protein tyrosine phosphatase, PTP 1 B.
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页码:46 / 54
页数:9
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