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Growth inhibition by Abl requires an interplay of its SH2 and tyrosine kinase domains
T Mattioni1, B J Mayer, D Picard
1Département de Biologie Cellulaire, Université de Genève, Switzerland.
Abstract:
Overexpression of c-Abl tyrosine kinase can be growth inhibitory in certain fibroblast cell lines. Using a series of conditional chimeras between Abl and Src, we have now further dissected the Abl protein to determine which domains are required for this function. We found that growth inhibition, unlike transformation by oncogenic forms of Abl, is dependent on the presence of the cognate SH2 and tyrosine kinase domains. Since growth inhibition correlates with low tyrosine kinase activity, it may involve highly specific interactions of target proteins with both domains without the processivity of phosphorylation associated with oncogenic Abl.
Insights
Overexpression of c-Abl tyrosine kinase inhibits fibroblast cell growth. This growth inhibition requires the SH2 and tyrosine kinase domains, suggesting specific protein interactions rather than high phosphorylation activity.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Overexpression of c-Abl tyrosine kinase can inhibit fibroblast cell growth.
- The specific domains of c-Abl responsible for this inhibitory function require further elucidation.
Purpose of the Study:
- To dissect the Abl protein and identify domains essential for growth inhibition.
- To differentiate the mechanisms of growth inhibition from oncogenic transformation by Abl.
Main Methods:
- Construction and analysis of conditional chimeras between Abl and Src proteins.
- Assessing the impact of domain deletions/substitutions on c-Abl function in fibroblast cell lines.
Main Results:
- Growth inhibition by c-Abl is dependent on the presence of its SH2 and tyrosine kinase domains.
- This function is distinct from the transformation mediated by oncogenic Abl variants.
- Growth inhibition correlates with reduced tyrosine kinase activity.
Conclusions:
- Specific interactions involving the SH2 and tyrosine kinase domains, rather than high phosphorylation activity, mediate c-Abl's growth inhibitory effects.
- These findings provide insights into the nuanced roles of c-Abl in cell growth regulation.