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Functional interaction between SHPTP1 and the Lyn tyrosine kinase in the apoptotic response to DNA damage
K Yoshida1, S Kharbanda, D Kufe
1Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Abstract:
The Lyn protein-tyrosine kinase is activated in the cellular response to DNA-damaging agents. Here we demonstrate that Lyn associates constitutively with the SHPTP1 protein-tyrosine phosphatase. The SH3 domain of Lyn interacts directly with SHPTP1. The results show that Lyn phosphorylates SHPTP1 at the C-terminal Tyr-564 site. Lyn-mediated phosphorylation of SHPTP1 stimulates SHPTP1 tyrosine phosphatase activity. We also demonstrate that treatment of cells with 1-beta-D-arabinofuranosylcytosine and other genotoxic agents induces Lyn-dependent phosphorylation and activation of SHPTP1. The significance of the Lyn-SHPTP1 interaction is supported by the demonstration that activation of Lyn contributes in part to the apoptotic response to ara-C treatment and that SHPTP1 attenuates this response. These findings support a functional interaction between Lyn and SHPTP1 in the response to DNA damage.
Insights
Lyn protein-tyrosine kinase interacts with SHPTP1 phosphatase, enhancing its activity in response to DNA damage. This interaction influences cellular apoptosis, highlighting a key pathway in DNA repair mechanisms.
Area of Science:
- Cellular biology
- Molecular oncology
- Biochemistry
Background:
- The Lyn protein-tyrosine kinase plays a role in cellular responses to DNA damage.
- The SHPTP1 protein-tyrosine phosphatase is involved in regulating cellular signaling pathways.
Purpose of the Study:
- To investigate the interaction between Lyn and SHPTP1 in the context of DNA damage.
- To elucidate the functional consequences of this interaction on cellular responses, including apoptosis.
Main Methods:
- Co-immunoprecipitation assays to demonstrate Lyn-SHPTP1 association.
- In vitro kinase assays to assess Lyn-mediated phosphorylation of SHPTP1.
- Cellular treatment with genotoxic agents (e.g., 1-beta-D-arabinofuranosylcytosine) followed by analysis of Lyn and SHPTP1 activity.
- Assessment of apoptosis levels in response to genotoxic stress and modulation of Lyn/SHPTP1 activity.
Main Results:
- Lyn constitutively associates with SHPTP1, with the SH3 domain of Lyn directly interacting with SHPTP1.
- Lyn phosphorylates SHPTP1 at the Tyr-564 site, which stimulates SHPTP1's tyrosine phosphatase activity.
- Genotoxic agents induce Lyn-dependent phosphorylation and activation of SHPTP1.
- Activation of Lyn contributes to apoptosis following treatment with 1-beta-D-arabinofuranosylcytosine, while SHPTP1 attenuates this apoptotic response.
Conclusions:
- A functional interaction exists between Lyn and SHPTP1 in the cellular response to DNA damage.
- Lyn-mediated activation of SHPTP1 is a key event in modulating the apoptotic outcome of genotoxic stress.
- This pathway represents a novel regulatory mechanism in DNA damage response and cell survival/death decisions.