ANALYSIS OF HUMAN C-ABL TYROSINE KINASE-ACTIVITY AND REGULATION IN S-POMBE

Citation
J. Walkenhorst et al., ANALYSIS OF HUMAN C-ABL TYROSINE KINASE-ACTIVITY AND REGULATION IN S-POMBE, Oncogene, 12(7), 1996, pp. 1513-1520
Citations number
40
Categorie Soggetti
Oncology,Biology,"Cell Biology
Journal title
ISSN journal
09509232
Volume
12
Issue
7
Year of publication
1996
Pages
1513 - 1520
Database
ISI
SICI code
0950-9232(1996)12:7<1513:AOHCTK>2.0.ZU;2-0
Abstract
c-Abl protein tyrosine kinase activity is tightly regulated in vertebr ate cells. Several mutations, including deletions of the SH3 domain, c an activate abl and convert it into an oncogene. To study c-Abl activi ty in a cellular environment likely to lack specific regulators, we ha ve expressed human c-Abl in Schizosaccharomyces pombe in an inducible fashion. c-Abl, but not a kinase inactive form of the molecule, causes growth arrest followed by death of the cells. Concomitant to Abl expr ession we observed extensive phosphorylation of endogenous proteins on tyrosine. Mutations in the SH2 domain or in the autophosphorylation s ite dramatically reduce the ability of Abl to confer the growth arrest phenotype and to phosphorylate endogenous proteins, suggesting a fund amental role of these structures in the activity of the enzyme. An SH3 domain deletion mutant of Abl is equally active as wild type c-Abl in yeast, even under conditions allowing detection of subtle differences . These results demonstrate that there is no intrinsic regulation of c -Abl kinase activity via the SH3 domain and suggest that the inhibitor y effect of the SH3 domain observed in mammalian cells is mediated by a factor that is absent in fission yeast. Expression of Abl in S.pombe provides a novel quantitative assay for Abl activity and regulation.